Use of Dinitrophenol in Nutritional Disorders : A Critical Survey of Clinical Results.

ArticleinAmerican journal of public health and the nation's health 24(10):1045-53 · November 1934with 15 Reads
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    In the sanctity of pure drug discovery, objective reasoning can become clouded when pursuing ideas that appear unorthodox, but are spot on physiologically. To put this into historical perspective, it was an unorthodox idea in the 1950’s to suggest that warfarin, a rat poison, could be repositioned into a breakthrough drug in humans to protect against strokes as a blood thinner. Yet it was approved in 1954 as Coumadin® and has been prescribed to billions of patients as a standard of care. Similarly, no one can forget the horrific effects of thalidomide, prescribed or available without a prescription, as both a sleeping pill and “morning sickness” anti-nausea medication targeting pregnant women in the 1950’s. The “thalidomide babies” became the case-in-point for the need of strict guidelines by the U.S. Food & Drug Administration (FDA) or full multi-species teratogenicity testing before drug approval. More recently it was found that thalidomide is useful in graft versus host disease, leprosy and resistant tuberculosis treatment, and as an anti-angiogenesis agent as a breakthrough drug for multiple myeloma (except for pregnant female patients). Decades of diabetes drug discovery research has historically focused on every possible angle, except, the energy-out side of the equation, namely, raising mitochondrial energy expenditure with chemical uncouplers. The idea of “social responsibility” allowed energy-in agents to be explored and the portfolio is robust with medicines of insulin sensitizers, insulin analogues, secretagogues, SGLT2 inhibitors, etc., but not energy-out medicines. The primary reason? It appeared unorthodox, to return to exploring a drug platform used in the 1930s in over 100,000 obese patients used for weight loss. This is over 80-years ago and prior to Dr Peter Mitchell explaining the mechanism of how mitochondrial uncouplers, like 2,4-dinitrophenol (DNP) even worked by three decades later in 1961. Although there is a clear application for metabolic disease, it was not until recently that this platform was explored for its merit at very low, weight-neutral doses, for treating insidious human illnesses and completely unrelated to weight reduction. It is known that mitochondrial uncouplers specifically target the entire organelle’s physiology non-genomically. It has been known for years that many neuromuscular and neurodegenerative diseases are associated with overt production of reactive oxygen species (ROSs), a rise in isoprostanes (biomarker of mitochondrial ROSs in urine or blood) and poor calcium (Ca2+) handing. It has also been known that mitochondrial uncouplers lower ROS production and Ca2+ overload. There is evidence that elevation of isoprostanes precedes disease onset, in Alzheimer’s Disease (AD). It is also curious, why so many neurodegenerative diseases of known and unknown etiology start at mid-life or later, such as Multiple Sclerosis (MS), Huntington Disease (HD), AD, Parkinson Disease, and Amyotrophic Lateral Sclerosis (ALS). Is there a relationship to a buildup of mutations that are sequestered over time due to ROSs exceeding the rate of repair? If ROS production were managed, could disease onset due to aging be delayed or prevented? Is it possible that most, if not all neurodegenerative diseases are manifested through mitochondrial dysfunction? Although DNP, a historic mitochondrial uncoupler, was used in the 1930s at high doses for obesity in well over 100,000 humans, and so far, it has never been an FDA-approved drug. This review will focus on the application of using DNP, but now, repositioned as a potential disease-modifying drug for a legion of insidious diseases at much lower and paradoxically, weight neutral doses. DNP will be addressed as a treatment for “metabesity”, an emerging term related to the global comorbidities associated with the over-nutritional phenotype; obesity, diabetes, nonalcoholic steatohepatitis (NASH), metabolic syndrome, cardiovascular disease, but including neurodegenerative disorders and accelerated aging. Some unexpected drug findings will be discussed, such as DNP’s induction of neurotrophic growth factors involved in neuronal heath, learning and cognition. For the first time in 80’s years, the FDA has granted (to Mitochon Pharmaceutical, Inc., Blue Bell, PA, USA) an open Investigational New Drug (IND) approval to begin rigorous clinical testing of DNP for safety and tolerability, including for the first ever, pharmacokinetic profiling in humans. Successful completion of Phase I clinical trial will open the door to explore the merits of DNP as a possible treatment of people with many truly unmet medical needs, including those suffering from HD, MS, PD, AD, ALS, Duchenne Muscular Dystrophy (DMD), and Traumatic Brain Injury (TBI).
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    2,4-Dinitrophenol (DNP) is reported to cause rapid loss of weight, but unfortunately is associated with an unacceptably high rate of significant adverse effects. DNP is sold mostly over the internet under a number of different names as a weight loss/slimming aid. It causes uncoupling of oxidative phosphorylation; the classic symptom complex associated with toxicity of phenol-based products such as DNP is a combination of hyperthermia, tachycardia, diaphoresis and tachypnoea, eventually leading to death. Fatalities related to exposure to DNP have been reported since the turn of the twentieth century. To date, there have been 62 published deaths in the medical literature attributed to DNP. In this review, we will describe the pattern and pathophysiology of DNP toxicity and summarise the previous fatalities associated with exposure to DNP.
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    Recent findings have elucidated roles for mitochondrial uncoupling proteins (UCPs) in neuronal plasticity and resistance to metabolic and oxidative stress. UCPs are induced by bioenergetic challenges such as caloric restriction and exercise and may protect neurons against dysfunction and degeneration. The pharmacological uncoupler 2,4-dinitrophenol (DNP), which was once prescribed to >100,000 people as a treatment for obesity, stimulates several adaptive cellular stress-response signaling pathways in neurons including those involving the brain-derived neurotrophic factor, the transcription factor cyclic AMP response element-binding protein (CREB), and autophagy. Preclinical data show that low doses of DNP can protect neurons and improve functional outcome in animal models of Alzheimer's and Parkinson's diseases, epilepsy, and cerebral ischemic stroke. Repurposing of DNP and the development of novel uncoupling agents with hormetic mechanisms of action provide opportunities for new breakthrough therapeutic interventions in a range of acute and chronic insidious neurodegenerative/neuromuscular conditions, all paradoxically at body weight-preserving doses.
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    There is a futile cycle of pump and leak of protons across the mitochondrial inner membrane. The contribution of the proton cycle to standard metabolic rate is significant, particularly in skeletal muscle, and it accounts for 20% or more of the resting respiration of a rat. The mechanism of the proton leak is uncertain: basal proton conductance is not a simple biophysical leak across the unmodified phospholipid bilayer. Equally, the evidence that it is catalysed by homologues of the brown adipose uncoupling protein, UCP1, is weak. The yeast genome contains no clear UCP homologue but yeast mitochondria have normal basal proton conductance. UCP1 catalyses a regulated inducible proton conductance in brown adipose tissue and the possibility remains open that UCP2 and UCP3 have a similar role in other tissues, although this has yet to be demonstrated.
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    The safety of obesity drugs has historically been poor. This and the stigmatisation of obesity in society ensured that a higher standard of safety for obesity drugs must be met. The authors review the safety disasters of obesity drugs that were withdrawn. The authors then review the safety of presently available drugs--benzphetamine, phendimetrazine, diethylpropion, phentermine, sibutramine and orlistat. The safety of rimonabant, a drug with a pending new drug application that has an independent effect on metabolic syndrome, is also reviewed. The authors compare the stage of obesity drug development to that of hypertension in the 1950s. As new and safer drugs with more downstream mechanisms are developed that have independent effects on the cardiovascular risks associated with obesity, third party reimbursement for obesity medicine is likely to improve. This may lead to obesity being treated like hypertension and other chronic diseases with long-term medication. With improved technological tools, the authors believe this process will be more rapid for obesity than it was for hypertension.
  • Article
    Bone morphogenetic protein 7 (BMP7) is a member of the transforming growth factor-β (TGF-β) superfamily of growth factors. In recent years, it has become clear that BMP7 is a very pleiotropic growth factor. As described in this review, it plays a pivotal role in the development of bone and kidney, and has only recently been demonstrated to also be crucially involved in differentiation of brown adipose tissue. Because BMP7 thus controls the development and maintenance of many physiological processes in the human body, aberrant expression of BMP7 is associated with a variety of diseases. This review gives a broad overview on the involvement of BMP7 in several pathological conditions, such as incomplete fracture healing, osteoarthritis, the development of bone metastases, renal fibrosis and obesity. Furthermore, the therapeutic potential of BMP7 in these disease states is discussed.
  • Article
    Methods for determination of 2-amino-4-nitrophenol and 4-amino-2-nitrophenol, metabolites of 2,4-dinitrophenol, were developed using differential pulse (DP) voltammetry and HPLC with amperometric and spectrophotometric detection. The applicability of these methods was tested by the determination of the analytes in model samples of urine after preliminary separation by solid-phase extraction. Voltammetry enabled parallel determination of both analytes, but its application in real matrix was severely limited due to the interference of other compounds present in urine. HPLC allowed the determination in real urine matrix down to micromolar concentrations; amperometric detection proved to be more sensitive and selective than the spectrophotometric one.
  • Book
    Full-text available
    Public health faces a new kind of drug problem with the growing prevalence of so–called ‘enhancement drugs’ that have the potential to improve human attributes and abilities. The widespread availability of such drugs has generated a new and growing audience of users. People are seeking out enhancement drugs in a quest to improve their bodies and minds—to look younger and more beautiful, to be stronger, happier and more intelligent. These types of drugs share a few similarities with recreational or addictive drugs—such as heroin, cocaine, ecstasy and ‘legal highs’— but also attract people who do not necessarily perceive themselves as ‘drug users’ and are vulnerable to cultural pressures to optimise their bodies. Manufacturers and retailers around the world are tapping into the demand for such drugs by harnessing innovations in science and medicine, as well as improvements in transport and communication networks. Significantly, in the case of illicit markets, retailers are able to circumvent national laws and regulation with creative and persuasive marketing strategies via the Internet. Often their customers are duped or remain unaware of the considerable harms associated with usage of these drugs, a situation that presents a threat to public health and throws up challenges for healthcare systems around the world
  • Article
    Activating mutations in BRAF are the most common genetic alterations in melanoma. Inhibition of BRAF by small molecules leads to cell-cycle arrest and apoptosis. We show here that BRAF inhibition also induces an oxidative phosphorylation gene program, mitochondrial biogenesis, and the increased expression of the mitochondrial master regulator, PGC1α. We further show that a target of BRAF, the melanocyte lineage factor MITF, directly regulates the expression of PGC1α. Melanomas with activation of the BRAF/MAPK pathway have suppressed levels of MITF and PGC1α and decreased oxidative metabolism. Conversely, treatment of BRAF-mutated melanomas with BRAF inhibitors renders them addicted to oxidative phosphorylation. Our data thus identify an adaptive metabolic program that limits the efficacy of BRAF inhibitors.
  • Article
    Full-text available
    Background: The use of cellular models as tools in drug discovery is almost universal. However, in disease areas such as metabolic diseases, are they relevant to the process and do they add value? Objective: In this article, we explore the variety of cellular models now used in drug discovery in metabolic diseases as revealed by publication. We have tried to make some connections between drug phenotypes in these models with clinical parallels. We also ask the question as to whether such models add value in the drug discovery process. This overview is not about recombinant cell systems used in target-based screening; rather, we focus on in vitro, including ex vivo, models as physiological systems in drug discovery in obesity and diabetes. Conclusion: In terms of building target confidence, in vitro models are often the only mechanistic link to human systems early in a projects life. Many of the current targets in metabolic diseases in the early discovery phase are not yet clinically supported, let alone validated. In this respect, therefore, in vitro models warrant a place in the critical path in early discovery. In terms of any predictive role for decision-making today, this is much more difficult and is more likely pushed to a supporting role as part of a wider package. However, there is a rapid rate of advancement in this field and future developments hold much promise.
  • Article
    4β-cinnamoyloxy,1β,3α-dihydroxyeudesm-7,8-ene (CDE) extracted from Verbesina persicifolia induces bioenergetic collapse in rat liver mitochondria (RLM), monitored as a fall in the respiratory control index and ADP/O values. This fall in energy is accompanied by a protonophore effect and membrane potential (ΔΨ) collapse, demonstrating that CDE behaves as a typical uncoupling agent. However, when examining the effect of CDE in detail, we found that it acts as a "mild" uncoupler because it drops ΔΨ and increases respiratory state 4. The proposed mechanism is based on the interaction of CDE with membrane protein cytochrome C oxidase, which is implicated in proton permeability, and with the respiratory chain for the generation of reactive oxygen species which mediate and regulate the activity of the above membrane protein. Considering the energy collapse, "mild" uncoupling, and the fact that CDE is largely used in folk medicines, this extract may be viewed as a potentially effective anti-obesity drug and a natural lead compound for developing new natural uncouplers against obesity.
  • Chapter
    Human brown adipose tissue (BAT) is experimentally modeled to better understand the biology of this important metabolic tissue, and also to enable the potential discovery and development of novel therapeutics for obesity and sequelae resulting from the persistent positive energy balance. This chapter focuses on translation into humans of findings and hypotheses generated in nonhuman models of BAT pharmacology. Given the demonstrated challenges of sustainably reducing caloric intake in modern humans, potential solutions to obesity likely lie in increasing energy expenditure. The energy-transforming activities of a single cell in any given tissue can be conceptualized as a flow of chemical energy from energy-rich substrate molecules into energy-expending, endergonic biological work processes through oxidative degradation of organic molecules ingested as nutrients. Despite the relatively tight coupling between metabolic reactions and products, some expended energy is incidentally lost as heat, and in this manner a significant fraction of the energy originally captured from the environment nonproductively transforms into heat rather than into biological work. In human and other mammalian cells, some processes are even completely uncoupled, and therefore purely energy consuming. These molecular and cellular actions sum up at the physiological level to adaptive thermogenesis, the endogenous physiology in which energy is nonproductively released as heat through uncoupling of mitochondria in brown fat and potentially skeletal muscle. Adaptive thermogenesis in mammals occurs in three forms, mostly in skeletal muscle and brown fat: shivering thermogenesis in skeletal muscle, non-shivering thermogenesis in brown fat, and diet-induced thermogenesis in brown fat. At the cellular level, the greatest energy transformations in humans and other eukaryotes occur in the mitochondria, where creating energetic inefficiency by uncoupling the conversion of energy-rich substrate molecules into ATP usable by all three major forms of biological work occurs by two primary means. Basal uncoupling occurs as a passive, general, nonspecific leak down the proton concentration gradient across the membrane in all mitochondria in the human body, a gradient driving a key step in ATP synthesis. Inducible uncoupling, which is the active conduction of protons across gradients through processes catalyzed by proteins, occurs only in select cell types including BAT. Experiments in rodents revealed UCP1 as the primary mammalian molecule accounting for the regulated, inducible uncoupling of BAT, and responsive to both cold and pharmacological stimulation. Cold stimulation of BAT has convincingly translated into humans, and older clinical observations with nonselective 2,4-DNP validate that human BAT’s participation in pharmacologically mediated, though nonselective, mitochondrial membrane decoupling can provide increased energy expenditure and corresponding body weight loss. In recent times, however, neither beta-adrenergic antagonism nor unselective sympathomimetic agonism by ephedrine and sibutramine provide convincing evidence that more BAT-selective mechanisms can impact energy balance and subsequently body weight. Although BAT activity correlates with leanness, hypothesis-driven selective β3-adrenergic agonism to activate BAT in humans has only provided robust proof of pharmacologic activation of β-adrenergic receptor signaling, limited proof of the mechanism of increased adaptive thermogenesis, and no convincing evidence that body weight loss through negative energy balance upon BAT activation can be accomplished outside of rodents. None of the five demonstrably β3 selective molecules with sufficient clinical experience to merit review provided significant weight loss in clinical trials (BRL 26830A, TAK 677, L-796568, CL 316,243, and BRL 35135). Broader conclusions regarding the human BAT therapeutic hypothesis are limited by the absence of data from most studies demonstrating specific activation of BAT thermogenesis in most studies. Additionally, more limited data sets with older or less selective β3 agonists also did not provide strong evidence of body weight effects. Encouragingly, β3-adrenergic agonists, catechins, capsinoids, and nutritional extracts, even without robust negative energy balance outcomes, all demonstrated increased total energy expenditure that in some cases could be associated with concomitant activation of BAT, though the absence of body weight loss indicates that in no cases did the magnitude of negative energy balance reach sufficient levels. Glucocorticoid receptor agonists, PPARg agonists, and thyroid hormone receptor agonists all possess defined molecular and cellular pharmacology that preclinical models predicted to be efficacious for negative energy balance and body weight loss, yet their effects on human BAT thermogenesis upon translation were inconsistent with predictions and disappointing. A few new mechanisms are nearing the stage of clinical trials and may yet provide a more quantitatively robust translation from preclinical to human experience with BAT. In conclusion, translation into humans has been demonstrated with BAT molecular pharmacology and cell biology, as well as with physiological response to cold. However, despite pharmacologically mediated, statistically significant elevation in total energy expenditure, translation into biologically meaningful negative energy balance was not achieved, as indicated by the absence of measurable loss of body weight over the duration of a clinical study.
  • Article
    Nonalcoholic fatty liver disease (NAFLD) affects one in three Americans and is a major predisposing condition for the metabolic syndrome and type 2 diabetes (T2D). We examined whether a functionally liver-targeted derivative of 2,4-dinitrophenol (DNP), DNP-methyl ether (DNPME), could safely decrease hypertriglyceridemia, NAFLD, and insulin resistance without systemic toxicities. Treatment with DNPME reversed hypertriglyceridemia, fatty liver, and whole-body insulin resistance in high-fat-fed rats and decreased hyperglycemia in a rat model of T2D with a wide therapeutic index. The reversal of liver and muscle insulin resistance was associated with reductions in tissue diacylglycerol content and reductions in protein kinase C epsilon (PKCε) and PKCθ activity in liver and muscle, respectively. These results demonstrate that the beneficial effects of DNP on hypertriglyceridemia, fatty liver, and insulin resistance can be dissociated from systemic toxicities and suggest the potential utility of liver-targeted mitochondrial uncoupling agents for the treatment of hypertriglyceridemia, NAFLD, metabolic syndrome, and T2D.
  • Article
    An outbreak of cataracts in 1935 caused by dinitrophenol (DNP), the active ingredient of popular diet pills, highlighted the inability of the Food and Drug Administration (FDA) to prevent harmful drugs from entering the marketplace. Just two years earlier, the FDA used horrific images of ocular surface injury caused by cosmetics at the World’s Fair in Chicago to garner public support for legislative reform. The FDA had to walk a fine line between a public awareness campaign and lobbying Congress while lawmakers debated the need for consumer protection. The cataract outbreak of 1935 was conspicuous in the medical literature during the height of New Deal legislation, but questions persist as to how much it affected passage of the proposed Food, Drug, and Cosmetic Act (of 1938). The legislation languished in committee for years. The cataract outbreak probably had little impact on the eventual outcome, but medical opinion concerning the safety of DNP may have contributed to the voluntary withdrawal of the diet drug from the market. We review the DNP cataract outbreak and examine it in context of the challenges facing regulatory reform at that time.
  • Article
    The identification of functional brown adipose tissue in human adults has intensified interest in exploiting thermogenic energy expenditure for the purpose of weight management. However, food intake and energy expenditure are tightly regulated and it is generally accepted that variation in one component results in compensatory changes in the other. In the context of weight loss, additional biological adaptations occur in an attempt to further limit weight loss. In the present review, we discuss the relationship between increasing energy expenditure and body weight in humans, including the effects of cold exposure. The data raise the possibility that some processes, particularly those involved in thermogenesis, induce less compensatory food intake for a given magnitude of additional energy expenditure, a state we term the 'thermogenic disconnect'. Although cold exposure increases thermogenesis and can putatively be exploited to induce weight loss, there are multiple adaptive responses to cold, of which many actually reduce energy expenditure. In order to optimally exploit either cold itself or agents that mimic cold for thermogenic energy expenditure, these non-thermogenic cold responses must be considered. Finally, the relative contribution of brown adipose tissue vs other thermogenic processes in humans remains to be defined. However, overall the data suggest that activation of cold-induced thermogenic processes are promising targets for interventions to treat obesity and its secondary metabolic complications. (J Diabetes Invest, doi:10.1111/j.2040-1124.2011.00158.x, 2011).
  • Article
    Full-text available
    Background: A membrane-penetrating cation, dodecyltriphenylphosphonium (C12TPP), facilitates the recycling of fatty acids in the artificial lipid membrane and mitochondria. C12TPP can dissipate mitochondrial membrane potential and may affect total energy expenditure and body weight in animals and humans. Methods: We investigated the metabolic effects of C12TPP in isolated brown-fat mitochondria, brown adipocyte cultures and mice in vivo. Experimental approaches included the measurement of oxygen consumption, carbon dioxide production, Western blotting, magnetic resonance imaging and bomb calorimetry. Results: In mice, C12TPP (50 μmol/(day • kg body weight)) in the drinking water significantly reduced body weight (12%, P<0.001) and body fat mass (24%, P<0.001) during the first 7 days of treatment. C12TPP did not affect water palatability and intake or the energy and lipid content in feces. The addition of C12TPP to isolated brown-fat mitochondria resulted in increased oxygen consumption. Three hours of pre-treatment with C12TPP also increased oligomycin-insensitive oxygen consumption in brown adipocyte cultures (P<0.01). The effects of C12TPP on mitochondria, cells and mice were independent of uncoupling protein 1 (UCP1). However, C12TPP treatment increased the mitochondrial protein levels in the brown adipose tissue (BAT) of both wild-type and UCP1-KO mice. Pair-feeding revealed that one-third of the body weight loss in C12TPP-treated mice was due to reduced food intake. C12TPP treatment elevated the resting metabolic rate (RMR) by up to 18% (P<0.05) compared with pair-fed animals. C12TPP reduced the respiratory exchange ratio (RER), indicating enhanced fatty acid oxidation in mice. Conclusions: C12TPP combats diet-induced obesity by reducing food intake, increasing the RMR and enhancing fatty acid oxidation.International Journal of Obesity accepted article preview online, 18 August 2016. doi:10.1038/ijo.2016.146.
  • Article
    Full-text available
    2,4-Dinitrophenol (2,4-DNP), a yellowish compound, has historically been used in the manufacture of dyes, explosives, and fungicides. As it uncouples mitochondrial oxidative phosphorylation, the compound was also used as an antiobesity agent early in the past century. The compound was subsequently banned by the United States Food and Drug Administration in 1938 due to its potentially fatal adverse effects, including hyperthermia, cataract, agranulocytosis, hepatoxicity, nephrotoxicity, and cardiotoxicity. However, the popularity of 2,4-DNP as a slimming aid has appeared to increase again in recent years. The Hong Kong Hospital Authority Toxicology Reference Laboratory recently confirmed two cases of self-administered 2,4-DNP with different clinical presentations to hospitals in the area. Here we describe those two cases, in an attempt to underscore the potential of misuse of this substance by body-conscious groups among the Chinese population.
  • Article
    The use of 2,4-dinitrophenol (DNP) has regained popularity as a weight loss aid in the last two decades due to increased marketing to bodybuilders and the increasing availability of this banned substance via the Internet. 2,4-DNP is a drug of narrow therapeutic index and toxicity results in hyperthermia, diaphoresis, tachycardia, tachypnoea and possible cardiac arrest and death. Skin toxicity from 2,4-DNP has not been reported since the 1930s. We report a case of a 21-year-old bodybuilding enthusiast who presented with a toxic exanthem after taking 2,4-DNP, and describe the first skin biopsy findings in a case of 2,4-DNP toxicity.
  • Article
    Full-text available
    Obesity is associated with premature mortality, impaired quality of life, and large healthcare costs. However, treatment options remain quite limited. Here we studied potential anti-obesity effects of a novel cationic mitochondrial uncoupler, C4R1 (derivative of rhodamine 19) in C57Bl/6 mice. Obesity was induced by long-term (eight weeks) high fat diet feeding at thermoneutrality. The treated group of mice received consecutively two doses of C4R1 in drinking water (30 and 12-14 μmol/kg daily) during 30 days. Effects of C4R1 were dose-dependent. After six days of C4R1 treatment at dose 30 μmol/kg daily, food intake was reduced by 68%, body weight by 19%, and fat mass by 21%. Body weight decrease was explained partly by reduced food intake and partly by increased metabolism, likely resulting from uncoupling. Body fat reduction upon C4R1 treatment was associated with improved lipid utilization estimated from decrease in respiratory quotient to the minimal level (0.7). Interestingly, the classical uncoupler 2,4-dinitrophenol at similar dose (27 μmol/kg daily) did not have any effect. Our results are relevant to the search for substances causing mild uncoupling of mitochondria that could be a promising therapeutic strategy to treat obesity.
  • Article
    We report the case of a 50-year-old obese man (115 kg body mass at 1.77 m height), who started taking 2,4-dinitrophenol (DNP) for weight reduction 44 days before his death. After 43 days of taking DNP, the man showed signs of intoxication with nausea, vomiting, and attacks of sweating. After admission to a hospital where the man concealed his DNP intake, sinus tachycardia, tachypnea, and general unrest were noted. The patient died 9 h after the onset of those symptoms. Upon autopsy, a yellowing of palms and soles was striking. The initially uncertain cause of death could only be clarified by the forensic toxicological examinations and subsequent police investigations. Finally, the man had a total intake of 12.3 g of DNP in 44 days which is relatively high compared to other lethal DNP intoxications.
  • Article
    L’identification d’un nouveau type d’adipocyte, l’adipocyte brite, distinct des adipocytes blancs et bruns jusqu’ici décrits, associée à la mise en évidence par imagerie de tissu adipeux brun chez l’homme adulte, ont renouvelé nos connaissances sur la biologie des tissus adipeux. Les propriétés de dissipation de l’énergie et de forte consommation de métabolites font des adipocytes bruns et brite des candidats attractifs pour la lutte contre les maladies métaboliques telles que le diabète et l’obésité. Cette revue présente ces récentes découvertes et l’espoir thérapeutique qu’elles révèlent.
  • Article
    In the early 1930s, the industrial chemical dinitrophenol found widespread favor as a weight-loss drug, due principally to the work of Maurice Tainter, a clinical pharmacologist from Stanford University. Unfortunately the compound's therapeutic index was razor thin and it was not until thousands of people suffered irreversible harm that mainstream physicians realized that dinitrophenol's risks outweighed its benefits and abandoned its use. Yet, it took passage of the Food, Drug, and Cosmetic Act in 1938 before federal regulators had the ability to stop patent medicine men from selling dinitrophenol to Americans lured by the promise of a drug that would safely melt one's fat away.
  • Sudden Death from Dinitrophenol Poisoning Report of a Case with Autopsy Low Oxygen Tensions and Temperatures on the Actions and Toxicity of Dinitrophenol
    • F E Poole
    • R B Haining
    Poole, F. E., and Haining, R. B. Sudden Death from Dinitrophenol Poisoning. Report of a Case with Autopsy. J.A.M.A., 102:1141, 1934. 17. Tainter, M. L. Low Oxygen Tensions and Temperatures on the Actions and Toxicity of Dinitrophenol. J. Pharm. Exper. Therap., 51:45, 1934. 18. Rabinowitch, I. M., and Fowler, A. F.
  • Toxicity of Dinitrophenol
    • H H Haft
    Haft, H. H. Toxicity of Dinitrophenol. J.A.M.A., 101:1171, 1933.
  • The Influence of Some New Nitroderivatives on the Cellular Metabolism and on Body Temperature
    • C Heymans
    Heymans, C. The Influence of Some New Nitroderivatives on the Cellular Metabolism and on Body Temperature. J. Pharm. Exper. Therap., 51: 144, 1934. 33. Kracke, R. R. Personal Communication.
  • The Rate of Blood Flow in Patients Receiving Dinitrophenol Agranulocytic Angina Following Ingestion of Dinitrophenol
    • H Rosenblum
    Rosenblum, H. The Rate of Blood Flow in Patients Receiving Dinitrophenol. In press. 36. Bohn, S. S. Agranulocytic Angina Following Ingestion of Dinitrophenol. J.A.M.A. 103:249, 1934.
  • Nitrophenine: Cellular Oxidation
    • Courdouan
    Courdouan. Nitrophenine: Cellular Oxidation. Progrps Med., 41:1738, 1933
  • Hyperthermic and Cardiovascular Actions of Dinitro-a-naphthol in the Dog
    • C Heymans
    • J J Bouckaert
    Heymans, C., and Bouckaert, J. J. Hyperthermic and Cardiovascular Actions of Dinitro-a-naphthol in the Dog. Arch. Intern. de Pharm. et de Therap., 35:63, 1928. 3. Leymann. Accidents in the Manufacture of Nitrophenol and Nitrochlor-Compounds. Concordia, 9:55, 1902.
  • Studies on the Action (Thermol)
    • H Magne
    • Mayer
    Magne, H., Mayer, Studies on the Action (Thermol). Ann. de Physiol. Biol., 8:1-167, 1932
  • Report of a Toxic Manifestation Due to Dinitrenal
    • S Hirsch
    Hirsch, S. Report of a Toxic Manifestation Due to Dinitrenal. J.A.M.A., 102:950, 1934
  • Actions of Dinitrophenol with the Use of Balanced and Unbalanced Diets Promis- 101:193, in the Manufacture of Concordia, A., of Plantefol, Dinitrophenol et de Physicochem. L. ct al. 1-2-4 Actions Febrile, Therap Repeated Antiseptic Doses
    • W C Cutting
    • M L J A M A Tainter
    Cutting, W. C., and Tainter, M. L. Actions of Dinitrophenol with the Use of Balanced and Unbalanced Diets. J.A.M.A., 101:2p99, 1933. Promis- 101:193, J.A.M.A., et de Therap., in the Manufacture of Concordia, A., of Plantefol, Dinitrophenol et de Physicochem. L. ct al. 1-2-4 Actions Febrile, Therap., Dinitrophenol. Fatal 48:410, 1933. Repeated Antiseptic Doses, Ibid, 49:187. J. H., and DeEds, in Diabetic Dogs. F. Arch. Carbohydrate Metabolism, in Animals with Dinitrophenol. Basal Am. J. on an Experimental Proc. Soc. Exper. Biol. in Diet, on Life of the White Rat. in Obesity and Re-Report. J.A.M.A., Useof 2-4 Dini-Brit. M. J., Metabolic rDINITROPHENOL IN NUTRITIONAL DISORDERS 105
  • Detection a-Dinitrophenol, New Drug Obesity
    • A Bolliger
    Bolliger, A. Detection a-Dinitrophenol, New Drug Obesity. M. J. Australia, 1:367
  • Dini-Actions Underactivity The New Eng Sudden Death Report of a Case with 1934. I. and Fowler
    • H Dintenfass
    • An
    • An Report
    • Accelerator
    • Compara-Soc
    • Exper
    • J H Biol
    • H J Goldsmith
    • R G Hoskins
    Dintenfass, H. An Report of An Accelerator of Compara-Soc. Exper. Biol. & J. H., and Goldsmith, H. Dini-Actions Underactivity. in J. Hoskins, R. G. The New Eng. J. Med., 210: A Case of J.A.M.A., 102:1147, Sudden Death Report of a Case with 1934. I. and Fowler, A. F. to Dini-J.A.M.A., 102:1219, Dinitrophenol J.A.M.A., 102:1844, Ear Complication from Dinitrophenol Medication
  • tive Effects of Dinitrophenol and Thyroxin on Tad-pole Metamorphosis
    • C C Cutting
    • M L Tainter
    Cutting, C. C., and Tainter, M. L. tive Effects of Dinitrophenol and Thyroxin on Tad-pole Metamorphosis. Proc. Med., 31:97, 1933
  • Chronic Toxicity of Dinitrophenol: Renal Function Clinical Circulatory Effects of Dinitrophenol
    • J A M A B Cutting
    • W Todd
    • J C Sanford
    • A Butt
    • E M Hickey
    J.A.M.A., 101:1171, 1933. 27. Schulte, T. L., and Tainter, M. L. Chronic Toxicity of Dinitrophenol: Renal Function. Proc. Soc. Exper. Biol. & Med., 31:1163, 1934. 28. Stockton, A. B., and Cutting, W. C. Clinical Circulatory Effects of Dinitrophenol. J.A.M.A. In press. 29. Todd, J. C., and Sanford, A. H. Clinical Diagnosis by Laboratory Methods, 1928. 6th ed., p. 363. 30. Tainter, M. L., Cutting, W. C., Wood, D. A., and Proescher, F. Arch. Path. In press. 31. Hoffman, A. M., Butt, E. M., and Hickey, N.
  • Use of Dinitrophenol in Obesity and Related Coniditions. A Progress Report The Use of 2-4 Dinitrophenol as a Metabolic Stimulant
    • M L Tainter
    • A B Stockton
    • W Cutting
    Tainter, M. L., Stockton, A. B., and Cutting, W. C. Use of Dinitrophenol in Obesity and Related Coniditions. A Progress Report. J.A.M.A., 101:1472, 1933. 7. Dunlop, D. M. The Use of 2-4 Dinitrophenol as a Metabolic Stimulant. Brit. M. J., 3820:524, 1934.
  • Antiseptic Tests and Actions of Some Isomers Actions of Dinitrophenol in Diabetic Dogs
    • J Pharmacol
    • Exper
    • M L Therap
    • J H Boyes
    • F Deeds
    J. Pharmacol. & Exper. Therap., 48:410, 1933. Miscellaneous Actions of Dinitrophenol. Repeated Administrations, Antidotes, Fatal Doses, Antiseptic Tests and Actions of Some Isomers. Ibid, 49:187. Tainter, M. L., Boyes, J. H., and DeEds, F. Actions of Dinitrophenol in Diabetic Dogs. Arch. Intern. de Pharm. et de Therap., 45:235, 1933. Hall, V. E., Field, J., Sahyun, M., Cutting, W.
  • Report of a Toxic Manifestation Due to " Dinitrenal Allergic Reaction to Dinitrophenol Report of a Case Report of a Case Dintenfass, H. An Ear Complication from Dinitrophenol Medication
    • Dinitrophenol
    • M A J Canad
    • G M Frumess
    Dinitrophenol. Canad. M. A. J., 30:128, 1934. 19. Hirsch, S. Report of a Toxic Manifestation Due to " Dinitrenal." J.A.M.A., 102:950, 1934. 20. Frumess, G. M. Allergic Reaction to Dinitrophenol. Report of a Case. J.A.M.A., 102:1219, 1934. 21. Jackson, H., and Duvall, A. I. Dinitrophenol Poisoning. Report of a Case. J.A.M.A., 102:1844, 1934. 22. Dintenfass, H. An Ear Complication from Dinitrophenol Medication. J.A.M.A., 102:838, 1934. 23. Guerbet. L'Expertise Chimique Dans Les Cas D'Intoxication Par le Dinitrophenol, 1918. Ministere de l'Armement et des Fabrications de Guerre. Conference Pour l'Etude de la Toxicite des Explosifs (Paris).
  • Report of a Case Courdouan. Nitrophenine: An Accelerator of Cellular Oxidation Comparative Effects of Dinitrophenol and Thyroxin on Tadpole Metamorphosis
    • G A Toxicity Of Alpha-Dinitrophrenol
    • C C Tainter
    G. A. Toxicity of Alpha-Dinitrophrenol. Report of a Case. J.A.M.A., 101:1053, 1933. 10. Courdouan. Nitrophenine: An Accelerator of Cellular Oxidation. Progrps Med., 41:1738, 1933. 11. Cutting, C. C., and Tainter, M. L. Comparative Effects of Dinitrophenol and Thyroxin on Tadpole Metamorphosis. Proc. Soc. Exper. Biol. & Med., 31:97, 1933. 12. Cutting, W. C., Rytand, D., and Tainter, M.
  • Chronic Toxicity of Dinitrophenol: Renal Function
    • T L Schulte
    • M L Tainter
    Schulte, T. L., and Tainter, M. L. Chronic Toxicity of Dinitrophenol: Renal Function. Proc. Soc. Exper. Biol. & Med., 31:1163, 1934.
  • Detection and Estimation of a-Dinitrophenol, New Drug for the Treatment of Obesity. M. J. Australia, 1:367, 1934. 25. Matzger, E. Can Sensitivity to Dinitrophenol be Determined by Skin Tests?
    • A Bolliger
    24. Bolliger, A. Detection and Estimation of a-Dinitrophenol, New Drug for the Treatment of Obesity. M. J. Australia, 1:367, 1934. 25. Matzger, E. Can Sensitivity to Dinitrophenol be Determined by Skin Tests? J.A.M.A., 103:253, 1934. 26. Haft, H. H. Toxicity of Dinitrophenol.
  • During the clinical use of sodium dinitrophenol (1-2-4) in obese patients, the occasional appearance of subjective symptoms such as tachycardia, dyspnea and profuse diaphoresis1 suggested the necessity of investigating the effects of the drug on the circulation.Thirteen patients with apparently normal cardiovascular systems were selected for this study. Six of the group were placed at bed rest in the hospital, and control observations of blood pressure, pulse rate, vital capacity and venous pressure made regularly at 8 a. m., 2 p. m. and 7 p. m. The control period was continued until at least three consecutive results were in close agreement. A mean of three or more control results was taken as the base. The control period was never less than three days and was sometimes as long as five days. A quantity of 300 mg. of sodium dinitrophenol was then administered orally in three divided doses each day,
  • Article
    Within the past year, dinitrophenol has been used extensively as a means of reducing weight. However, its possible harmful effects have not been realized sufficiently until very recently. In papers by Anderson, Reed and Emerson,1 Geiger,2 Poole and Haining,3 and Tainter and Wood,4 fatal results from the use of dinitrophenol have been reported. In all probability, a great many more poisonings and fatalities have occurred, since many druggists are dispensing dinitrophenol without a physician's prescription, under both the name of dinitrophenol and various proprietary names. A case of toxic hepatitis with intense jaundice following the use of dinitrophenol is here reported.REPORT OF CASE B. R., a white woman, unmarried, aged 26, had used various reducing diets because she weighed too much for her stature (58 inches, 145 cm.). The past history and family history were essentially negative. The patient began taking dinitrophenol, Feb. 18, 1934,
  • Article
    We have recently shown in a series of papers1 that alpha-dinitrophenol markedly augments metabolism in doses which are not demonstrably harmful. As this drug may have a number of important clinical applications, it seems desirable to present a summary report of its pharmacologic and therapeutic effects, and to point out certain potential dangers in, and limitations to, its use.During the World War, dinitrophenol was called to the attention of French physicians by cases of poisoning from it in munitions factories. Only incomplete investigations of the actions of the compound were made at that time, as judged by published reports. Recently, Magne, Mayer, Plantefol and others2 have extended or completed work begun some years previously but reported simultaneously with our entirely independent studies. We are in general agreement with them as to the main pharmacologic actions of the drug. The experimental studies have been extended by us and
  • Blumgart and his co-workers1 have shown the close relationship that exists between the height of the metabolic rate and the velocity of the blood flow. This relationship was demonstrated on hypothyroid and hyperthyroid patients with the use of the radium method2 for the determination of the speed of the flow of blood. These observations were abundantly confirmed by Tarr, Oppenheimer and Sager3 and by Gargill,3a who used the sodium dehydrocholate method4 in studying circulation time.The conception that the amount of work done by the heart is partly determined by the metabolic rate has been substantiated and clinically applied in recent years. It has become a well established fact that when serious heart disease is associated with hyperthyroidism the cardiac embarrassment is grossly aggravated when the level of the metabolism is high and is much improved when the metabolic rate is lowered.5 This improvement
  • Prof. C. Heymans of Ghent has recently revived interest in the fever producing properties of nitrated naphthols,1 a demonstration of which stimulated Tainter and his colleagues to study alpha-dinitrophenol. Others had shown also that the latter drug causes an increase in cellular oxidation.2 Because of its metabolic stimulating qualities, this agent was proposed and used by Cutting, Mehrtens and Tainter3 for the clinical treatment of obesity, hypothyroidism and similar depressed metabolic states. They especially warned against its toxicity, stating that "there are limitations to and possible dangers from the use of the drug clinically. It should be used only under strictly controlled conditions." Since hearing this report we have had a case of intolerance to alpha-dinitrophenol which prompted us to inquire into the toxicity of the compound in an effort to determine contraindications to its use and methods for detecting untoward effects.Perkins, in a comprehensive review
  • In a short note recently published,1 attention was drawn to a fatality that occurred from dinitrophenol poisoning. Since this drug is being widely used as a metabolic stimulant, and since the complete details of this case were available only to us, it seemed desirable to publish a full account of it, together with the pathologic observations. This case report will also emphasize the fact which we have consistently stressed;2 namely, that careless or reckless use of this drug may have unfortunate consequences.REPORT OF CASE History.— H. G., a man, aged 37, a graduate of a Vienna medical school but unlicensed to practice in this country, called on one of us (T.) to obtain information regarding dinitrophenol as a metabolic stimulant. He stated that he was suffering from general glandular dysfunction, including a hypopituitarism resulting from a previous sphenoiditis. His libido was gone and no therapy had been
  • The increasing number of cases reported in recent years presenting the syndrome of agranulocytic angina or malignant neutropenia has excited comment from many observers. Numerous drugs, organisms and toxins have been connected with the disease entity but definite confirmatory clinical and experimental data have been lacking.Kracke1 in 1932 was able to induce the characteristic blood picture in rabbits with small subcutaneous injections of benzene following the lead of Selling2 in 1916 in demonstrating the leukotoxic effects of benzene on myeloblastic tissues. Kracke also produced a marked leukopenia with subcutaneous injections of orthooxybenzoic acid and by the intravenous injections of hydroquinone. He was unsuccessful in depressing the leukocyte count with a group of other substances, as acetphenatidin, peralga (barbituric acid and amidopyrine), dial, resorcinol, pyrocatechin, orthocresol, para and metaoxybenzoic acid and 50 per cent alcohol. To one rabbit he administered from 5 to 10 grains (0.3 to 0.65
  • The study here reported was undertaken to determine whether it is possible by the use of the available methods of skin testing to anticipate the skin eruptions and other signs of hypersensitiveness that not infrequently occur with the therapeutic use of dinitrophenol. Without consideration of the controversial subjects of allergy, atopy or anaphylaxis and without referring to the none too clear conceptions of antigen antibody reactions as applied to nonprotein substances, I wish to submit the results of my experiment.METHODS The three possible methods of skin testing were employed for the direct test, and the intradermal method alone was used for the indirect test.
  • During recent months the medical literature has been characterized by numerous reports of cases illustrating unfavorable reactions and deaths following the use of dinitrophenol, the barbiturates and amidopyrine. In the instances of these reactions following therapy with the barbiturates and amidopyrine, several observers have cited a resulting neutropenia or agranulocytic angina. There is reference made, however, to only one case of agranulocytic angina following the ingestion of dinitrophenol.1 The report includes a case in which agranulocytosis developed after the ingestion of dinitrophenol over a period of two weeks, the patient recovering following treatment. Since no mention was made in this case regarding the amount of the drug taken during the two weeks or of the blood picture, and since in no other report of dinitrophenol poisoning has there been reference made to an ensuing neutropenia (those reports including a blood picture showed essentially normal white blood counts, while the