Effects of anabolic precursors on serum testosterone concentrations and adaptations to resistance training in young men

Exercise Biochemistry Laboratory, Department of Health and Human Performance, Iowa State University, Ames, IA 50011, USA.
International journal of sport nutrition and exercise metabolism (Impact Factor: 2.44). 09/2000; 10(3):340-59.
Source: PubMed


The effects of androgen precursors, combined with herbal extracts designed to enhance testosterone formation and reduce conversion of androgens to estrogens was studied in young men. Subjects performed 3 days of resistance training per week for 8 weeks. Each day during Weeks 1, 2, 4, 5, 7, and 8, subjects consumed either placebo (PL; n = 10) or a supplement (ANDRO-6; n = 10), which contained daily doses of 300 mg androstenedione, 150 mg DHEA, 750 mg Tribulus terrestris, 625 mg Chrysin, 300 mg Indole-3-carbinol, and 540 mg Saw palmetto. Serum androstenedione concentrations were higher in ANDRO-6 after 2, 5, and 8 weeks (p <.05), while serum concentrations of free and total testosterone were unchanged in both groups. Serum estradiol was elevated at Weeks 2, 5, and 8 in ANDRO-6 (p <.05), and serum estrone was elevated at Weeks 5 and 8 (p <.05). Muscle strength increased (p <.05) similarly from Weeks 0 to 4, and again from Weeks 4 to 8 in both treatment groups. The acute effect of one third of the daily dose of ANDRO-6 and PL was studied in 10 men (23 +/- 4 years). Serum androstenedione concentrations were elevated (p <.05) in ANDRO-6 from 150 to 360 min after ingestion, while serum free or total testosterone concentrations were unchanged. These data provide evidence that the addition of these herbal extracts to androstenedione does not result in increased serum testosterone concentrations, reduce the estrogenic effect of androstenedione, and does not augment the adaptations to resistance training.

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Available from: Gregory A Brown, Oct 09, 2015
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    • "TT plus AAS. In the search for appropriate androgens taken by athletes, Brown et al. (2000b) focused their attention on exogenous androstenedione and androstenediol, steroids which in the human body are converted into more biologically active compounds. Assuming that TT would enhance the rate of that conversion, and in consequence increase the effectiveness of relatively small amounts of those pro-hormones, the same authors carried out more comprehensive studies on the biological effect of TT taken concurrently with androstenediol (Brown et al., 2001) or androstenedione (Brown et al., 2000a). "
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    ABSTRACT: Herbal and nutritional supplements are more and more popular in the western population. One of them is an extract of an exotic plant, named Tribulus terrestris (TT). TT is a component of several supplements that are available over-the-counter and widely recommended, generally as enhancers of human vitality. TT is touted as a testosterone booster and remedy for impaired erectile function; therefore, it is targeted at physically active men, including male athletes. Based on the scientific literature describing the results of clinical trials, this review attempted to verify information on marketing TT with particular reference to the needs of athletes. It was found that there are few reliable data on the usefulness of TT in competitive sport. In humans, a TT extract used alone without additional components does not improve androgenic status or physical performance among athletes. The results of a few studies have showed that the combination of TT with other pharmacological components increases testosterone levels, but it was not discovered which components of the mixture contributed to that effect. TT contains several organic compounds including alkaloids and steroidal glycosides, of which pharmacological action in humans is not completely explained. One anti-doping study reported an incident with a TT supplement contaminated by a banned steroid. Toxicological studies regarding TT have been carried out on animals only, however, one accidental poisoning of a man was described. The Australian Institute of Sport does not recommend athletes' usage of TT. So far, the published data concerning TT do not provide strong evidence for either usefulness or safe usage in sport.
    Journal of Human Kinetics 06/2014; 41:99-105. DOI:10.2478/hukin-2014-0037 · 1.03 Impact Factor
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    • "Experimental studies using T. terrestris extracts have demonstrated an increase in sexual function in rats which has been attributed to an increase in testosterone, dihydrotestosterone, and dehydroepiandrosterone.[89] One clinical study has also demonstrated that T. terrestris extract increases body's natural testosterone levels and thereby improves male sexual performance and helps build muscle.[10] However, as sexual dysfunction has been shown to be more prevalent in the aging population,[1] the evaluation of investigational drugs in aged and sexually sluggish males for their aphrodisiac and sexual tonic activity is a better predictor for their efficacy in the clinical setting. "
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    ABSTRACT: To study the effect of acute and repeated dose administration of lyophilized aqueous extract of the dried fruits of Tribulus terrestris (LAET) on sexual function in sexually sluggish male albino rats. Aphrodisiac activity of the test drug was evaluated in terms of exhibited sexual behavior. In order to assess the effect of chronic T. terrestris exposure on the hypothalamus--pituitary--gonadal axis, testosterone level estimation and sperm count were carried out. Twenty-eight-day oral toxicity studies were carried out to evaluate the long-term effects of the LAET administration on different body systems. A dose-dependent improvement in sexual behavior was observed with the LAET treatment as characterized by an increase in mount frequency, intromission frequency, and penile erection index, as well as a decrease in mount latency, intromission latency, and ejaculatory latency. The enhancement of sexual behavior was more prominent on chronic administration of LAET. Chronic administration of LAET produced a significant increase in serum testosterone levels with no significant effect on the sperm count. No overt body system dysfunctions were observed in 28-day oral toxicity study. Findings of the present study validate the traditional use of T. terrestris as a sexual enhancer in the management of sexual dysfunction in males.
    Journal of Pharmacology and Pharmacotherapeutics 03/2012; 3(1):43-7. DOI:10.4103/0976-500X.92512
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    • "The manufacturers claim that this plant extract promotes testosterone production in the testes, and Ceylon spinach has been shown to stimulate Leydig cells directly in rats, leading to significant increases in testosterone output [7]. However, Brown et al. found that a cocktail of androgen precursors and herbal extracts including I3C did not cause a rise in free or total testosterone [8]. The predominant mode of action of I3C in ActivaTe Xtreme™ is the modulation of oestrone metabolism. "
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    ABSTRACT: A 19 year old male attended his GP with a history of "fluid retention", lack of libido and erectile dysfunction. He was found to have a high serum testosterone, and a raised luteinising hormone. After further investigations, the patient admitted to taking a supplement called ActivaTe Xtreme, obtained from an internet source, to address his low libido. ActivaTe Xtreme contains active ingredients which increase serum testosterone levels by several independent mechanisms that are not associated with luteinising hormone suppression. Urine analyses for synthetic anabolic steroids were negative, and urinary testosterone, epitestosterone and other androgens were normal. This biochemical pattern is not the same as that seen with anabolic steroids (i.e. raised testosterone, suppressed luteinising hormone and abnormal urine steroid profile). The issue of self medication with performance enhancing compounds needs to be carefully considered in order to avoid expensive and invasive investigations, missing an underlying pathology or misdiagnosing a patient. This case also raises the spectre of yet another "performance enhancing" product that may cause difficulty for those trying to ensure that sport remains on a "hormonally" equal basis.
    Clinica chimica acta; international journal of clinical chemistry 10/2011; 412(21-22):1999-2001. DOI:10.1016/j.cca.2011.06.028 · 2.82 Impact Factor
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