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Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To investigate the role of insulin on Ca2+ regulation of vascular smooth muscle cells (VSMC) in hypertension, the effect of insulin on Ca2+ transport and intracellular free calcium concentration ([Ca2+]i) was measured in cultured VSMC from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Insulin produced a substantial increase in 45Ca uptake as well as [Ca2+]i in quiescent cultured VSMC. The stimulatory effects of insulin were completely inhibited by diltiazem, and partially by H-7, TMB-8, and 5-N,N(hexamethylene)amiloride (HMA), but not by W-7 or trifluoroperazine. Insulin-sensitive 45Ca uptake of SHR VSMC was significantly smaller than that of WKY VSMC. Insulin-sensitive increase in [Ca2+]i of SHR VSMC was also smaller than that of WKY VSMC. It is concluded that insulin increases 45Ca uptake, leading to an increase in [Ca2+]i, presumably through the voltage-dependent Ca2+ channel, intracellular Ca2+ release, or protein kinase C mediated mechanisms in cultured VSMC. A blunted response of insulin-sensitive Ca2+ uptake and [Ca2+]i in SHR VSMC suggests the differential regulation of Ca2+ transport in response to insulin in primary hypertension.
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PMID:Decreased insulin-sensitive Ca2+ transport in cultured vascular smooth muscle cells from spontaneously hypertensive rats. 128 39

Diabetes mellitus (DM)-linked metabolic alterations and hypertension concomitantly accelerate or precipitate cerebrovascular and coronary heart disease, nephropathy, retinopathy and widespread macroangiopathy, thereby conferring to diabetic patients a very high risk of morbidity, disability and early death. Therefore, the long-term care for diabetic patients should be aimed at concomitant metabolic and blood pressure (BP) control. Dietary measures are indispensable; a high fibre, low fat, low salt diet is recommended, complemented with caloric restriction and physical exercise when body weight is above the ideal. Antidiabetic pharmacotherapy involves an unresolved dilemma. The desired achievement of euglycemia necessitates effective levels of insulin, but hyperinsulinemia (due to parenteral [over]treatment in insulin-dependent DM) is suspected to promote atherogenesis and represents a coronary risk factor and perhaps even facilitates hypertension. Considering antihypertensive pharmacotherapy, thiazide-type or loop diuretics are problematic drugs in DM because they can aggravate metabolic alterations. These agents also seem to exert only a limited preventive or regressive effect on left ventricular hypertrophy (LVH); beta-blockers are also not considered ideal, since they decrease the awareness of hypoglycemia and tend to promote glucose intolerance. Unselective beta-blockers in particular promote peripheral ischemia and insulin-induced hypoglycemia, while beta-blockers without intrinsic sympathomimetic activity lower serum HDL-cholesterol. Calcium antagonists and ACE inhibitors have equivalent antihypertensive efficacy, do not impair carbohydrate and lipid homeostasis or peripheral perfusion and can effectively improve LVH. Certain ACE inhibitors may even slightly ameliorate abnormal insulin sensitivity and plasma glucose levels. While alpha-blockers share most of these desirable properties, these agents are more prone to precipitate orthostatic hypotension in the diabetic patient. The non-thiazide diuretic indapamide and the serotonin2-antagonist ketanserin also combine antihypertensive efficacy with metabolic neutrality. The ultimate goal of therapy is to improve life prognosis. In essential hypertension, conventional drug treatment based on diuretics in high dosage satisfactorily reduced cerebrovascular but not coronary complications or sudden death. In diabetic patients, the influence of antihypertensive therapy on prognosis has not been assessed prospectively. Based on retrospective analyses, Warram et al reported a 3.8 times higher mortality in diabetics treated with diuretics alone, than in diabetics with untreated hypertension (Arch Intern Med. 1991;151:1350). H. H. Parving calculated that effective BP control in patients with diabetic nephropathy might reduce 10 year-mortality from about 65 to 20 percent (J Hypertension. 1990; 8[Suppl 7]:187).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Antihypertensive therapy in diabetic patients. 128 10

Glucose intolerance and noninsulin-dependent diabetes are commonly associated with hypertension. Epidemiological data suggest that this association is independent of age and obesity. Much evidence indicates that the link between diabetes and essential hypertension is hyperinsulinemia. When hypertensive patients whether obese or of normal weight are compared with matched normotensive control subjects, an increased plasma insulin response to a glucose challenge is consistently observed. Studies using insulin glucose clamp techniques in combination with tracer glucose infusion and indirect calorimetry have demonstrated that the insulin resistance in hypertensive subjects is located in muscles and restricted to glycogen synthesis. The relations between hyperinsulinemia and blood pressure do not prove that the relationship is a causal one. However, at least four mechanisms may link hyperinsulinemia with hypertension: Na+ retention, sympathetic nervous system overactivity, disturbed membrane ion transport and proliferation of vascular smooth muscle cells. Diuretics and beta-blockers may enhance insulin resistance, which is not affected by calcium antagonists, but decreased by the ACE inhibitor captopril. Weight reduction and regular physical exercise can improve insulin sensitivity and decrease blood pressure values. These nonpharmacological interventions should be more strongly recommended to diabetic and nondiabetic hypertensive patients.
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PMID:Hyperinsulinemia, insulin resistance and essential hypertension. 130 12

In an open two-month study with an initial placebo period, the effect of enalapril on glucose tolerance, insulin (IRI) sensitivity and lipid profile was evaluated in 20 patients with mild to moderate essential hypertension. The following results were obtained: 1. Enalapril produced a favourable effect of blood pressure both in monotherapy and if combined with a diuretic. 2. Therapy did not lead to significant differences in blood glucose, IRI or IRI/glucose increase at 1 or 2 hours of oral glucose tolerance test either in patients with monotherapy or combination therapy, and with normal or disturbed glucose tolerance, respectively. 3. Serum lipids (total and HDL-cholesterol and triglycerides) did not change significantly in any group of patients.
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PMID:Metabolic effects of enalapril in the treatment of essential hypertension. 130 25

There is evidence that the cytosolic free Ca2+, protein kinase C, and the Na(+)-H+ antiport cross-communicate with one another through positive and negative feedback mechanisms, thereby maintaining cellular Ca2+ and pH homeostasis. This triumvirate may play a role in the development of insulin resistance--a common characteristic of both essential hypertension and non-insulin-dependent diabetes mellitus. Circulating cells from patients with essential hypertension and non-insulin-dependent diabetes mellitus demonstrate elevated cytosolic free Ca2+, increased protein kinase C activity, or both, and these perturbations are associated with augmented activity of the Na(+)-H+ antiport. If present in other cells (e.g., striated muscle cells and adipocytes), these alterations could underlie insulin resistance in essential hypertension and non-insulin-dependent diabetes mellitus.
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PMID:The roles of cell Ca2+, protein kinase C and the Na(+)-H+ antiport in the development of hypertension and insulin resistance. 133 4

The digitalis-like substance (DLS), insulin resistance, and hyperglycemia are ascribed important roles in the pathogenesis of essential hypertension. The relationship between DLS and glycemia (insulinemia) was investigated in the present study. The levels of glycemia, insulinemia and DLS were measured during oral glucose load in a group of 18 subjects with various blood pressure values. Fasting levels of glycemia and insulinemia were in each subject within the physiological range and no correlation was found to exist between the fasting levels of DLS and glycemia (insulinemia). One hour after oral glucose load the increase of glycemia and insulinemia was significantly higher in the group of subjects with SBP > 140 and/or DBP > 90 mmHg than in normotensive subjects (p < 0.001). The increase in glycemia (insulinemia) was followed by a decrease of DLS. This contrary trend could be expressed as a significant inverse correlation between the change in plasma DLS and the change in glycemia (r = -0.660 p = 0.0039), and also between the change in plasma DLS and the change insulinemia (r = -0.687 p = 0.0023). These findings are assumed to suggest certain mechanisms involved in the pathophysiology of essential hypertension. (Tab. 3, Fig. 2, Ref. 20.)
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PMID:[Endogenous digitalis-like substance in relation to glycemia and insulinemia]. 133 11

Insulin resistance is a frequently occurring abnormality. Although there can be insensitivity to any of insulin's actions, insulin resistance par excellence is a decreased insulin-mediated whole-body glucose disposal rate. A distinction is made between primary and secondary insulin resistance. Primary insulin resistance is of unknown origin, is only partially experimentally reproducible, and is essentially irreversible (spontaneously or by treatment). In addition, it is both pathway-specific (ie, glucose storage) and organ-specific (mostly skeletal muscle), and is compatible with a postreceptor defect in insulin action. Primary insulin resistance is found in a proportion (approximately 25%) of otherwise healthy people, in non-insulin-dependent diabetes mellitus, essential hypertension, and some forms of dyslipidemia. The idea of an insulin resistance syndrome derives from the striking pattern of overlap among these clinical conditions. Their tendency to cluster in the same individuals is evident from both cross-sectional and longitudinal observations. It is proposed that the insulin resistance syndrome is a large constellation of interrelated changes in metabolic, anthropometric, and hemodynamic variables centered around insulin resistance or hyperinsulinemia. There is a significant genetic component, a predisposing influence for non-insulin-dependent diabetes mellitus, hypertension, dyslipidemia, and possibly, a distinct atherogenic potential.
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PMID:The insulin resistance syndrome. 134 29

In view of the likely prohypertensive effects of hyperinsulinemia and the presence of insulin resistance in primary hypertension, the effects of various antihypertensive therapies on insulin sensitivity need to be identified. The evidence strongly supports major beneficial effects of weight reduction and aerobic exercise. Deleterious effects have been shown for diuretics and most beta-blockers, whereas probable beneficial effects have been seen with alpha-blockers, one angiotensin converting enzyme inhibitor, and various calcium entry blockers. Improvement of insulin sensitivity and reduction of plasma insulin levels are desirable attributes of antihypertensive therapy that should be more carefully considered in the future.
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PMID:Effects of antihypertensive therapy on insulin resistance. 134 22

Both haemodynamic and metabolic variables have been shown to be related to the fibre composition and capillary density of skeletal muscle in man. In the present study, the change of several metabolic variables during beta-blockade was investigated and related to muscle fibre composition and capillary density in 28 men with essential hypertension. They had been given atenolol (50 mg/day) or metoprolol (200 mg/day) or propranolol (160 mg/day) for 4-12 months. Serum triglycerides increased during treatment and individual changes were significantly inversely correlated with capillary density. Insulin concentrations in the fasting state and at the end of an i.v. glucose tolerance test were significantly higher during beta-blockade, and individual changes were inversely correlated with capillary density. Furthermore, body weight increased and heart rate decreased, changes that were also correlated with capillary density. It is concluded that many of the previously but poorly understood large interindividual differences in response to beta-blocker treatment may be explained by the degree of development of the capillary net in muscle tissue. Obesity, physical training as well as genetic factors are known determinants of capillary density.
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PMID:The metabolic and circulatory response to beta-blockade in hypertensive men is correlated to muscle capillary density. 136 76

The effect of treatment of hypertension with nifedipine on plasma renin activity, blood serum level of aldosterone in the course of renin test, and cortisol and growth hormone concentrations after stimulation with insulin hypoglycemia was followed during two weeks of treatment in 40 patients with essential hypertension. No significant differences in the secretion of the hormones studied, as compared to the patients with the normal arterial blood pressure, were found. After nifedipine treatment no significant changes in the secretion of aldosterone, cortisol and growth hormone were observed despite a significant fall in the arterial blood pressure while there was a moderate stimulatory effect on renin secretion. The results obtained indicate that nifedipine has only small effect on the hormonal system of patients with essential hypertension.
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PMID:[Effect of nifedipine treatment on the renin-aldosterone system and secretion of cortisol and growth hormone in patients with essential hypertension]. 136 91


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