J E Hall's research while affiliated with University of Mississippi and other places

Publications (153)

Article
Full-text available
Obesity is the most common cause of human essential hypertension in most industrialized countries. Although the precise mechanisms of obesity hypertension are not fully understood, considerable evidence suggests that excess renal sodium reabsorption and a hypertensive shift of pressure natriuresis play a major role. Sympathetic activation appears t...
Article
New methods in molecular biology and genetics have made possible many of the dramatic advances in physiological research that have occurred in recent years. For those of us who spend most of our time in the research laboratory, it si sometimes difficult to avoid a research-oriented, reductionist mind-set when discussing physiology with students. Th...
Article
The renin-angiotensin system (RAS) is one of the body's most powerful regulators of arterial pressure and body fluid volumes. Although the acute effects of angiotensin II (AngII), the primary active component of the RAS, on arterial pressure are mediated primarily by peripheral vasoconstriction, its chronic BP effects are closely intertwined with v...
Article
Chronic insulin infusion in rats increases mean arterial pressure (MAP) and reduces glomerular filtration rate (GFR), but the mechanisms for these actions are not known. This study tested whether thromboxane synthesis inhibition (TSI) would attenuate the renal and blood pressure responses to sustained hyperinsulinemia. Male Sprague-Dawley rats were...
Article
To determine the site of origin of increased concentrations of plasma endothelin-1 in patients with severe preeclampsia. Twelve patients with severe preeclampsia undergoing an indicated abdominal delivery had endothelin-1 levels measured from plasma specimens drawn from right and left uterine and antecubital veins before delivery and after placenta...
Article
Steady-state insulin resistance results in a fasting hyperinsulinemia and is a common feature of type II diabetes mellitus and obesity. In this study, a systems analysis approach was used to study glucose homeostasis which is considered as the dynamic balance between glucose release by the liver and its uptake by the peripheral tissues as regulated...
Article
Obesity is a major cause of human essential hypertension. Recent studies point toward increased renal tubular reabsorption and abnormal renal pressure natriuresis in mediating obesity hypertension. The mechanisms for these renal changes appear to be multifactorial, including activation of the sympathetic nervous system and altered intrarenal histol...
Article
In human essential hypertension, and in all forms of experimental hypertension studied thus far, volume regulation and the relationship between blood pressure (BP) and sodium excretion (pressure natriuresis) are abnormal. Considerable evidence indicates that resetting of pressure natriuresis plays a key role in causing hypertension, rather than mer...
Article
Hyperinsulinemia has been reported to cause hypertension in rats; however, the renal and hemodynamic mechanisms are not known. In this study, changes in renal function, cardiac output (CO), and total peripheral resistance (TPR) were measured during chronic insulin infusion in eight rats (approximately 350 g). After a 4-day control period, a 7-day i...
Article
Full-text available
Graphic analyses have been used in the study of physiology as a means to better understand dynamic processes and to visualize the mechanisms of their interactions. A graphic analysis of glucose homeostasis was constructed by considering the main factors that influence glucose dynamics. The analysis is achieved by equating curves representing both t...
Article
In all forms of hypertension, including human essential hypertension, pressure natriuresis is abnormal because sodium excretion is the same as in normotension despite increased arterial pressure. Considerable evidence indicates that this resetting of pressure natriuresis plays a key role in causing hypertension, rather than merely occurring as an a...
Article
We have previously shown that obesity causes marked proliferation of extracellular matrix in die renal medulla, as well as increased renal interstitial fluid hydrostatic pressure, increased tubular reabsorption, and hypertension. In this study, we tested the hypothesis that renal medullary compression, caused by increased extracellular matrix and l...
Article
We have previously shown that chronic hypcrinsulinemia causes hypertension in rats and acute studies suggest that endothelial-derived nitric oxide (EDNO) may modulate the vascular actions of insulin. The present study was designed to determine whether blockade of EDNO synthesis with nitro-L-arginine methyl ester (L-NAME) exacerbates the hypertensiv...
Article
We investigated why resting heart rate is elevated in dogs fed a high saturated fat diet for 12.7 +/- 1.8 wk. Obese dogs exhibited elevated body weight (59%), blood pressure (14%), and heart rate (25%). Differences in resting heart rate (control, 58 +/- 5 beats/min; obese, 83 +/- 7 beats/min) were abolished after hexamethonium, indicating an autono...
Article
Hypertension is a well-recognized complication of obesity. However, the mechanisms for the development of obesity hypertension are not known. One mechanism proposed is that the hyperinsulinemia present in obese hypertensive patients causes hypertension via sodium retaining and/or sympathetic nervous system stimulatory effects. However, numerous stu...
Article
Insulin resistance and hyperinsulinemia have been postulated to be important in raising blood pressure in obese as well as lean hypertensive individuals. However, cause-and-effect relationships among these variables have not been clearly established. The three most widely used methods to assess insulin resistance in vivo (fasting plasma insulin, gl...
Article
In all forms of hypertension, including human essential hypertension, pressure natriuresis is reset to higher blood pressures. Because human essential hypertension is a heterogeneous disease, it is likely that there are multiple neurohumoral and intrarenal causes of abnormal pressure natriuresis and increased blood pressure. Weight gain is recogniz...
Article
Insulin resistance and the sympathetic nervous system have been suggested to be important factors in the blood pressure response to hyperinsulinemia. This study was designed to investigate whether the response to chronic hyperinsulinemia in 14-week-old SH rats (n = 6), which are reported to be insulin resistant and to have a hyperresponsive sympath...
Article
This study examined the control of renal hemodynamics and tubular function, as well as systemic hemodynamics, during obesity-induced hypertension in chronically instrumented conscious dogs. Mean arterial pressure, cardiac output, and heart rate were monitored 24 hours a day using computerized methods, water and electrolyte balances were measured da...
Article
If pressure natriuresis is to play an important role in arterial pressure control, renal perfusion pressure must have a long-term effect on urinary sodium excretion. The aim of this study was to quantitate the importance of renal perfusion pressure per se in controlling renal hemodynamics and electrolyte excretion chronically. Female mongrel dogs (...
Article
The purpose of this study was to examine the sequential changes in renal and cardiovascular function produced by chronic Benazepril administration at different stages of heart failure in dogs. Heart failure was produced by rapid ventricular pacing in five dogs with a normally functioning renin-angiotensin system (angiotensin normal, AN) and six dog...
Article
Recent work to elucidate the cause of obesity-associated hypertension has focused on insulin resistance and hyperinsulinemia. A significant amount of epidemiologic and correlational evidence suggests a link between these factors and obesity-associated hypertension, and acute insulin infusion studies have revealed renal, neural, and cardiovascular e...
Article
A 32-amino acid atrial natriuretic peptide (ANP)-like peptide, putatively synthesized by the kidney, has recently been isolated from human urine. This peptide, urodilatin (Uro), is structurally similar to the 28-amino acid ANP, suggesting that they might have similar actions on renal fluid and electrolyte excretion. The purpose of this study was to...
Article
The goal of this study was to examine the chronic blood pressure and renal actions of insulin in conscious rats and to determine whether the blood pressure response to insulin is salt-sensitive. The effects of chronic hyperinsulinemia were examined in three groups of Sprague-Dawley rats given low sodium (LS rats, 0.6 meq/day), normal sodium (NS rat...
Article
Atrial natriuretic peptide (ANP) may decrease cardiac output (CO) by lowering circulating blood volume (BV) or by altering the vasculature in a manner that would decrease venous return. The purpose of this study was to determine the role of decreased BV in mediating the decrease in CO during acute infusion of ANP. BV was measured by dilution of 51C...
Article
In normal subjects, high sodium intake causes little change in mean arterial pressure (MAP). However, MAP is sodium sensitive after reduction of kidney mass. The present study examined the role of increased renal artery pressure and decreased angiotensin II (ANG II) formation in maintaining sodium balance during high sodium intake in dogs with redu...
Article
Hyperinsulinemia and insulin resistance have been postulated to link obesity and hypertension. Evidence supporting this concept derives mainly from epidemiological studies showing a correlation between insulin resistance, hyperinsulinemia, and blood pressure and from short-term studies suggesting that insulin has renal and cardiovascular actions th...
Chapter
Evidence that the kidneys play a key role in blood pressure regulation comes from the fact that chronic abnormalities of blood pressure control, such as hypertension, almost always begin with some abnormality of renal function. For example, Goldblatt hypertension begins with stenosis of one or both of the renal arteries; mineralocorticoid hypertens...
Article
One-kidney, one-clip hypertension (1-K, 1-C HT) is initiated by increased preglomerular resistance which decreases nephron perfusion and causes several intrarenal changes that lead to increased mean arterial pressure (MAP). Elevated MAP serves to return nephron perfusion and sodium excretion to normal, so that fluid intake and output are balanced....
Article
The RAS is part of an extremely powerful feedback system for long-term control of blood pressure and volume homeostasis. Disturbances that tend to lower blood pressure, such as heart failure, cirrhosis, and peripheral vasodilation, cause sodium and water retention until blood pressure returns to normal due, in large part, to the combined actions of...
Article
Hyperinsulinemia has been postulated to link obesity and hypertension via the antinatriuretic actions of insulin. The main goal of this study was to quantitate the importance of the direct intrarenal actions of insulin, independent of systemic effects, in altering blood pressure and renal function. This was accomplished by determining the responses...
Article
A large body of correlational evidence relating plasma insulin levels and arterial pressure in obese hypertensives suggests that hyperinsulinemia may play a causal role in the development of hypertension in these subjects. However, experimental evidence supporting the ability of increased plasma insulin per se to increase blood pressure is lacking....
Article
This study examined the long-term actions of atrial natriuretic factor (ANF), at physiological levels, on renal function and mean arterial pressure (MAP) and the importance of Na intake and the renin-angiotensin-aldosterone system in modulating those effects. After a control period, ANF was infused intravenously at a rate of 10 ng.kg-1.min-1 for 7...
Article
Chronic intravenous infusions of atrial natriuretic peptide (ANP) have been shown to lower mean arterial pressure (MAP) in both normal and hypertensive animals. However, the importance of the renal actions of ANP in mediating this hypotension is unknown. This study was designed to determine whether physiological or pathophysiological increases in i...
Article
In all forms of chronic hypertension, the renal-pressure natriuresis mechanism is abnormal because sodium excretion is the same as in normotension despite the increased blood pressure. However, the importance of this resetting of pressure natriuresis as a cause of hypertension is controversial. Theoretically, a resetting of pressure natriuresis cou...
Article
Although acute infusions of atrial natriuretic peptide (ANP) often cause natriuresis, these effects are not sustained, possibly because of reductions in arterial pressure or other compensatory adaptations. The aim of this study was to determine whether physiological increases in intrarenal ANP levels cause sustained natriuresis if changes in arteri...
Article
Although hyperinsulinemia and increased adrenergic activity have been postulated to be important factors in obesity-associated hypertension, a cause and effect relation between insulin, catecholamines, and hypertension has not been established. The aim of this study was to determine whether chronic hyperinsulinemia, comparable with that found in ob...
Article
The aims of this study were to determine whether chronic hyperinsulinemia, comparable to that found in obese hypertensives, elevates mean arterial pressure (MAP) or potentiates the hypertensive effects of angiotensin II (ANG II). Studies were conducted in conscious dogs with kidney mass reduced by 70% in order to increase their susceptibility to hy...
Article
The RAS is part of an extremely powerful feedback system for long-term control of arterial pressure and volume homeostasis as illustrated in Figure 4. Disturbances that tend to lower blood pressure such as heart failure, cirrhosis, and peripheral vasodilation, cause sodium and water retention until blood pressure returns to normal due in large part...
Article
The aim of this study was to quantitate the effects of increases in atrial natriuretic peptide (ANP), within the pathophysiological range, on the acute pressure natriuresis mechanism and the role of the renin-angiotensin system (RAS) in modulating these effects. Renal hemodynamics and electrolyte excretion were measured in anesthetized dogs while r...
Article
The aim of this study was to examine the contribution of the renal nerves to the sodium retention in chronic congestive heart failure produced by rapid ventricular pacing. In 10 female dogs the left kidney was denervated and the urinary bladder was split to allow separate 24-h urine collection from an innervated and a denervated kidney in the same...
Article
The aim of this study was to determine whether chronic hyperinsulinemia, comparable to that found in obesity-associated hypertension, causes sustained increases in mean arterial pressure (MAP) or potentiates the hypertensive effects of angiotensin II (ANG II). Insulin infusion (0.5 or 1.0 mU/kg/min, IV), with plasma glucose held constant by IV gluc...
Article
The purpose of this study was to test the hypothesis that, in the presence of high circulating catecholamines, ACTH decreases renal excretory capability and that its natriuretic effects are caused by increased renal arterial pressure (RAP). In six conscious dogs, norepinephrine (NE, 0.4 micrograms.kg-1.min-1) alone for 5 days caused a small but sig...
Article
The aim of this study was to examine the importance of the renal nerves in mediating the sodium-retaining actions of angiotensin II (ANG II) during chronic sodium deprivation. In seven female dogs the left kidney was denervated and the urinary bladder was split, allowing continuous urine collection from separate innervated and denervated kidneys in...
Article
The purpose of this study is to determine the quantitative importance of the liver in mediating the increases in renal blood flow and glomerular filtration rate (GFR) that occur after elevation of plasma amino acids. A mixture of four amine acids (Gly, Ser, Ala, Pro at 0.075 mmol X kg-1 X min-1 total) was infused intravenously into normal anestheti...
Article
The aim of this study was to investigate the importance of the renal nerves in adaptation to chronic reductions in sodium intake. Conscious dogs with unilateral (n = 7) or bilateral (n = 4) renal denervation were studied. In dogs studied before and after bilateral denervation, there were no differences in urine volume (UO), Na excretion (UNaV), or...
Article
Our purpose was to determine whether renal autoregulatory capability is retained in pregnancy despite the marked renal vasodilation that occurs at this time. Renal blood flow and glomerular filtration rate (GFR) were measured in anesthetized pregnant (22-27 days gestation) and nonpregnant rabbits during step reductions in renal perfusion pressure f...
Article
The purpose of this study was to test the hypothesis that hyperglycemia, comparable with that found in uncontrolled diabetes mellitus, increases renal blood flow (RBF) and glomerular filtration rate (GFR) through a tubuloglomerular feedback (TGF) mechanism. We infused glucose intrarenally (0.1-0.3 g/min) into anesthetized dogs with normal kidneys (...