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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies in humans have shown that cortisol administration (200 mg/day) increases cardiac output, renal vascular resistance, glomerular filtration rate, plasma volume, extracellular fluid volume, exchangeable sodium, plasma glucose, insulin, renin substrate and atrial natriuretic peptide concentrations as well as urinary kallikrein excretion. Cortisol treatment decreases renin and angiotensin II concentrations while catecholamines and vasopressin are decreased or unchanged. We have clear evidence from a number of studies that cortisol-induced hypertension is modulated by, but not dependent on, exogenous sodium. The increase in cardiac output normally seen with cortisol administration is not essential for the blood pressure rise. The role of the increase in renal vascular resistance in the genesis of the hypertension is unclear. Studies using measurements of noradrenaline spillover and assessment of reflex function have not shown any increase in sympathetic nervous system activity but changes in vascular responsiveness, particularly to phenylnephrine and noradrenaline are marked. Cortisol is known to have a variety of effects on brain, heart, kidneys, blood vessels and body fluid volumes. To what extent the observed changes are epiphenomena, amplifiers or modulators, or are causal is unclear. Cortisol hypertension may reflect a complex interplay of these factors varying with the steroid concentrations achieved, underlying genetic factors and the particular experimental circumstances.
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PMID:Experimental studies on cortisol-induced hypertension in humans. 747 17

The metabolic syndrome is discussed in terms of insulin resistance linked to an increased regulation of metabolism by cortisol and fatty acids. This change in hormonal balance is associated with diabetes, android (visceral) obesity, hypertension, hypertriglyceridemia, hyperapobetalipoproteinemia and low concentrations of HDL; a cluster of risk-factors that predisposes to the development of premature atherosclerosis. It is proposed that the metabolic syndrome is accompanied by a derangement in the hypothalamic-pituitary-adrenal-axis such that the effects of cortisol are exaggerated relative to those of CRF. Excessive action of fatty acids and cortisol causes insulin resistance and increase the hepatic secretion of glucose and VLDL. Furthermore, cortisol can decrease the uptake of LDL by the liver. Cortisol in the presence of relatively high insulin concentrations can promote the deposition of energy and lead to obesity. Chronic treatment of rats with D-fenfluramine has been shown to decrease the release of cortisol and fatty acids in response to stress, and to improve insulin sensitivity. The effects of D-fenfluramine were also tested in male JCR:LA corpulent rats which are prone to develop atherosclerosis and myocardial lesions. D-fenfluramine improved insulin sensitivity, decreased the hypertriglyceridemia, and prevented the development of necrotic myocardial lesions caused by ischemia. The data presented demonstrates a link between excessive action of cortisol and fatty acids in predisposing to insulin resistance and the pathologies that are associated with the metabolic syndrome.
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PMID:Role of glucocorticoids and fatty acids in the impairment of lipid metabolism observed in the metabolic syndrome. 755 May 41

Preeclampsia is accompanied by amplification of the sodium retention that is a feature of normal pregnancy. Recent evidence suggests that mineralocorticoid receptor activation is increased in preeclampsia, but classic mineralocorticoids (aldosterone, 11-deoxycorticosterone) are not present in excess. Cortisol can act as a mineralocorticoid receptor agonist only when its renal inactivation to cortisone by 11 beta-hydroxy-steroid dehydrogenase is impaired, for example, in congenital enzyme deficiency and after administration of exogenous inhibitors (eg, licorice). Endogenous inhibitors of this enzyme have been detected in human urine and are increased in pregnancy. To establish whether cortisol causes mineralocorticoid excess in hypertensive pregnancy and whether endogenous inhibitors of 11 beta-hydroxysteroid dehydrogenase are responsible, we studied 25 hypertensive pregnant patients (13 with preeclampsia and 12 with gestational hypertension), 16 normotensive pregnant subjects, and 13 nonpregnant control subjects. Concentrations of plasma renin and aldosterone were increased in pregnancy, but less so in hypertensive pregnancy. Plasma potassium and urinary electrolytes were not different between the groups. Plasma cortisol was increased in pregnancy but not different in hypertensive pregnancy, and urinary cortisol, plasma and urinary cortisone, and urinary tetrahydrocortisol and tetrahydrocortisone were not different between the groups. Endogenous inhibitors of 11 beta-hydroxysteroid dehydrogenase were more active in urine from pregnant women but were not increased further in hypertensive pregnancy. There were no differences in these parameters between patients with preeclampsia and gestational hypertension. We conclude that deficient inactivation of cortisol to cortisone does not contribute to the sodium retention of normotensive or hypertensive pregnancy and that endogenous inhibitors of 11 beta-hydroxysteroid dehydrogenase have no evident pathophysiological significance in pregnancy.
Hypertension 1995 Apr
PMID:11 beta-Hydroxysteroid dehydrogenase and its inhibitors in hypertensive pregnancy. 772 7

Increasing evidence has accumulated for rapid nongenomic steroid actions in various cell systems and, more recently, for rapid aldosterone effects on the Na(+)-H+ antiport in human mononuclear leukocytes. The aim of the present study was to demonstrate a rapid, nongenomic aldosterone action in rat vascular smooth muscle cells as a key effector cell in cardiovascular regulation. Basal 22Na+ influx in quiescent vascular smooth muscle cells was 22.1 +/- 1.9 nmol/mg protein per minute (mean +/- SEM, n = 9). Aldosterone (1 nmol/L) stimulated influx to 28.6 +/- 1.5 nmol/mg protein per minute after 4 minutes (n = 9, P < .05), with a half-maximal effect between 0.1 and 0.5 nmol/L; the effects were inhibited by ethylisopropylamiloride, the specific inhibitor of the Na(+)-H+ exchanger, demonstrating the involvement of this transport system in rapid effects of aldosterone. Hydrocortisone (1 mumol/L) was ineffective, and fludrocortisone and deoxycorticosterone increased influx with half-maximal effects at approximately 0.5 nmol/L. Canrenone, a classic antagonist of aldosterone action, did not inhibit stimulation by aldosterone at a 1000-fold excess concentration. Aldosterone significantly stimulated intracellular inositol 1,4,5-trisphosphate levels (P < .05) after 30 seconds; the inhibitors of phospholipase C, neomycin and U-73122, inhibited aldosterone-stimulated Na+ influx and increase of intracellular inositol 1,4,5-trisphosphate. The rapid stimulation of sodium transport in vascular smooth muscle cells and the pharmacological characteristics of this effect are clearly incompatible with the classic, genomic pathway of steroid action and represent further evidence for nongenomic effects of aldosterone.
Hypertension 1995 Jan
PMID:Rapid effects of aldosterone on sodium transport in vascular smooth muscle cells. 784 42

There is much interest in the relationship of hypertension to hyperinsulinemia. Six male volunteers received cortisol, 50 mg orally four times daily, for 5 days. Plasma insulin concentration increased from 11.8 +/- 3.0 mU/L to 16.1 +/- 4.0 mU/L (P = .034). Fasting glucose increased from 4.7 +/- 0.3 to 5.8 +/- 0.1 mmol/L (P = .001). The insulin-to-glucose ratio was unchanged. Octreotide has been reported to lower blood pressure in obese, hyperinsulinemic, hypertensive patients. The hypothesis that cortisol-induced hypertension might be secondary to steroid-induced hyperinsulinemia was examined by determining whether reversal of hyperinsulinemia by octreotide would reverse cortisol-induced hypertension. Five healthy men were given two subcutaneous injections of 0.05 mg of octreotide before and on the fifth day of cortisol administration. Cortisol increased blood pressure, weight, plasma glucose concentration, and white cell count, with decreases in plasma potassium concentration and packed cell volume. Plasma cortisol concentrations were unchanged following octreotide in the control period but decreased after cortisol treatment. Insulin concentrations were reduced profoundly after octreotide, both in the control period (12.5 +/- 3.7 mU/L, falling to 1.1 +/- 0.3 mU/L at 30 min) and on cortisol (22.3 +/- 4.5 to 2.3 +/- 0.5 mU/L at 30 min). Octreotide did not lower pressure before or after cortisol treatment. Thus, octreotide was effective in lowering plasma insulin concentrations but di not lower blood pressure in normal subjects with cortisol-induced hypertension. These data do not support the notion that steroid-induced hyperinsulinemia is responsible for steroid-induced hypertension.
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PMID:Hyperinsulinemia is not a cause of cortisol-induced hypertension. 791 57

1. Cortisol-induced blood pressure rises in men are not accompanied by increases in plasma catecholamines. The present study examines the effects of cortisol on the sympathetic co-transmitter, neuropeptide Y (NPY). 2. Eight normal men were given cortisol 200 mg/day over 5 days and haemodynamic, metabolic and hormonal measures were taken. Plasma NPY-like immunoreactivity (NPY-LI) concentrations were measured by direct radio-immunoassay. 3. Cortisol significantly increased systolic, diastolic and mean arterial pressure, bodyweight, plasma glucose and total white cell concentration and decreased plasma potassium and total eosinophil count, as in previous studies. Plasma NPY concentrations were not altered significantly during cortisol treatment, but increased following cessation of cortisol treatment (P = 0.006). 4. The essentially unchanged pattern for NPY concentration with cortisol treatment resembles that previously reported for adrenaline and noradrenaline, but the increase in NPY on cortisol withdrawal was not seen for adrenaline or noradrenaline. These data do not support a role for sympathetic activation in the genesis of cortisol-induced hypertension.
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PMID:Neuropeptide Y in cortisol-induced hypertension in male volunteers. 795 53

The case is described of a 40-year-old female with severe hypertension and hypokalaemic metabolic alkalosis, due to prolonged liquorice ingestion. The pseudo-aldosterone-like effects of liquorice have always been attributed to glycyrrhizic acid, but its biochemical substrate has remained elusive. It is now known that glycyrrhetenic acid, the hydrolytic metabolite of glycerrhizic acid, is the active component of liquorice which causes inhibition of the peripheral metabolism of cortisol. Cortisol binds with the same affinity as aldosterone to the mineralocorticoid receptor resulting in a hypermineralocorticoid condition. Ingestion of liquorice may therefore result in retention of sodium and water, hypertension, hypokalaemia, alkalosis and suppression of the renin-aldosterone system. The literature on liquorice-induced hypertension is briefly reviewed with emphasis on the biochemical features of this mineralocorticoid excess syndrome.
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PMID:Liquorice-induced hypertension--a new understanding of an old disease: case report and brief review. 854 95

11 beta-Hydroxysteroid dehydrogenase type 2 (11 beta-HSD2) specifically modulates access of the mineralocorticoid aldosterone to the kidney mineralocorticoid type 1 receptors in a physiological environment in which there is a molar excess of cortisol. Cortisol and aldosterone have similar affinities for mineralocorticoid receptors. Mechanistically, 11 beta-HSD2 converts cortisol to cortisone. The other known isoform, 11 beta-HSD1, not only catalyzes the cortisol to cortisone reaction but also the reverse reaction, making it unlikely to play an important role in modulating the access of aldosterone to mineralocorticoid receptors. Mutations in the HSD11B2 gene (both exonic and intronic) have been demonstrated to cause reduced activity of this enzyme in the syndrome of apparent mineralocorticoid excess, a rare autosomal recessive disorder. We hypothesized that this locus is also involved in the etiology of essential hypertension. To test this locus and flanking chromosomal regions for allelic association and genetic linkage to essential hypertension, it is necessary to have informative genetic markers. To this end, we have refined the localization of 11 beta-HSD2 to 16q22.1. We genotyped subjects using the nearest flanking microsatellites (D16S301 and D16S496). We conducted an association study using black subjects with hypertensive end-stage renal disease, black normotensive control subjects, and black and white individuals from the general population. We used chi 2 analysis and Fisher's exact test to test for association with these candidate gene markers. No significant association was found between D16S301 and hypertension. However, a positive association with hypertension was found at the D16S496 microsatellite locus (chi 2 = 6.98, df = 1, P < or = .008). Our data suggest that HSD11B2 is associated with hypertension in our black subjects with hypertensive end-stage renal disease. The 16q22.1 chromosome region potentially harbors a candidate gene for essential hypertension. Confirmation of our findings in another independently ascertained group of hypertensive subjects will provide a basis for proceeding with sib-pair linkage analyses.
Hypertension 1996 Sep
PMID:Genetic association of 11 beta-hydroxysteroid dehydrogenase type 2 (HSD11B2) flanking microsatellites with essential hypertension in blacks. 879 36

1. We investigated the role of the autonomic nervous system (ANS) in cortisol induced hypertension using the technique of total autonomic blockade (AB). 2. Four healthy young males were given 50 mg cortisol 6 hourly for 6 days. On the day prior to, and the last day of, cortisol treatment, AB was produced using oral prazosin 1 mg, intravenous clonidine 300 micrograms, propranolol 0.2 mg/kg and atropine 2 mg. The adequacy of blockade was assessed using the haemodynamic response to Valsalva manoeuvre. 3. Cortisol produced a significant rise in systolic blood pressure (130 +/- 2 vs 110 +/- 1 mmHg, pre vs post cortisol; P < 0.01). On the final treatment day, AB augmented the increase in diastolic blood pressure (delta DBP), mean arterial pressure (delta MAP) and heart rate (delta HR) compared to the pretreatment day, delta DBP: 43 +/- 6 vs 17 +/- 4 mmHg, post vs pre cortisol, P < 0.005, delta MAP: 39 +/- 4 vs 14 +/- 4 mmHg, P < 0.001, delta HR: 45 +/- 5 vs 26 +/- 4 b.p.m., P < 0.05. The change in systolic blood pressure (delta SBP) was not statistically significant (32 +/- 4 vs 7 +/- 3 mmHg, P = 0.065). 4. These results suggest that the ANS exerts a modulating influence on the hypertensive effect of cortisol.
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PMID:Autonomic blockade amplifies cortisol-induced hypertension in man. 904 2

Abnormalities of cortisol production or metabolism are involved in the genesis of hypertension in Cushing's syndrome, apparent mineralocorticoid excess and liquorice abuse and possibly in chronic renal failure and essential hypertension. We have studied the physiological mechanisms by which cortisol raises blood pressure in short term studies of cortisol administration in normal men. Cortisol induced hypertension cannot be explained by increases in vasopressor or decreases in vasodepressor hormone concentrations, or by any increase in sympathetic nervous activity. The hypertension is accompanied by substantial sodium retention but a significant component of the blood pressure rise is sodium independent. The hypertension is characterized by an increase in cardiac output but a rise in output is not essential for the rise in blood pressure. Our working hypothesis is that cortisol induced hypertension is a consequence of increases in renal vascular resistance.
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PMID:Glucocorticoids and hypertension in man. 924 61


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