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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Though long standing diabetes mellitus is frequently accompanied by hypoaldosteronism, the role of insulin in this setting has never been clearly established. In the present study we have examined the direct effects of insulin on aldosterone production in rat zona glomerulosa cells in vitro. Insulin is shown to directly stimulate aldosterone production in a dose dependent manner, and to attenuate angiotensin II mediated aldosterone production, without affecting angiotensin II receptor binding kinetics. Insulin had no effect on aldosterone production mediated by the other physiological stimuli (K+ and ACTH). These data suggest a possible interaction between insulin and angiotensin II in the regulation of aldosterone secretion.
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PMID:In vitro effects of insulin on aldosterone production in rat zona glomerulosa cells. 131 36

Angiotensin II receptors on platelets were studied in 13 patients with uncomplicated type I diabetes mellitus and in 15 age-matched normal subjects. Receptor density on cells from the diabetic patients was 15% lower than the normal subjects (5.2 +/- 0.8 SD sites/platelet in diabetic patients and 6.4 +/- 0.8 in normals, P less than 0.001), but there were no differences in receptor affinity as measured by Kd (4.9 +/- 1.5 X 10(-10) mol/l in diabetic patients and 5.4 +/- 1.4 X 10(-10) mol/l in normals). Plasma concentrations of renin and angiotensin II were similar in both groups. The reduced density of angiotensin II receptors on platelets from patients with insulin-dependent diabetes may reflect a generalized abnormality of angiotensin II receptor regulation.
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PMID:Reduced number of angiotensin II receptors on platelets in insulin-dependent diabetes. 301 90

Glomerular angiotensin II receptors are reduced in number in early diabetes mellitus, which may contribute to hyperfiltration and glomerular injury. The time course and role of the renin-angiotensin-aldosterone system in the pathogenesis of the receptor abnormality were studied in male Sprague-Dawley rats made diabetic with streptozotocin (65 mg, iv). Glomerular angiotensin II receptors were measured by Scatchard analysis; insulin, renin activity, angiotensin II, and aldosterone were measured by RIA. Diabetes mellitus was documented at 24 h by a rise in plasma glucose (vehicle-injected control, 133 +/- 4; diabetic, 482 +/- 22 mg/dl; P less than 0.001) and a fall in plasma insulin (control, 53.1 +/- 5.7; diabetic, 35.6 +/- 4.0 microIU/ml; P less than 0.05). At 24 h glomerular angiotensin II receptor density was decreased by 26.5% in diabetic rats (control, 75.5 +/- 9.6 X 10(6); diabetic, 55.5 +/- 8.3 X 10(6) receptors/glomerulus; P less than 0.01). Receptor occupancy could not explain the defect, because there was reduced binding in diabetic glomeruli after pretreatment with 3 M MgCl2, a maneuver that caused dissociation of previously bound hormone. There was a progressive return of the receptor density toward normal over the 60 days following induction of diabetes, with diabetic glomeruli measuring 22.7%, 14.8%, and 3.7% fewer receptors than age-matched controls at 11 days, 1 month, and 2 months, respectively (r = 0.99; n = 4; P less than 0.01). Three lines of evidence suggested that reduced angiotensin II receptor density at 24 h was not due to down-regulation by angiotensin II: PRA and angiotensin II were identical in control and diabetic rats; angiotensin II infusion (50 ng/min) caused down-regulation in both control and diabetic rats, but the change in receptor density persisted (control, 33.6 +/- 6.9 X 10(6); diabetic, 18.5 +/- 1.3 X 10(6) receptors/glomerulus; P less than 0.05); and angiotensin-converting enzyme inhibition with enalapril caused receptor up-regulation, but the differences persisted (control, 105.5 +/- 21.2 X 10(6); diabetic, 67.1 +/- 3.0 X 10(6) receptors/glomerulus; P less than 0.05). Rats with chronic diabetes (7-60 days) had normal PRA and angiotensin II, but plasma aldosterone was elevated (control, 29.8 +/- 3.3; diabetic, 68.6 +/- 12.4 ng/dl; P less than 0.005). The return of angiotensin II receptor density to normal levels in chronic diabetes may be the result of receptor up-regulation by increased plasma aldosterone rather than recovery of the underlying defect.
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PMID:Reduced glomerular angiotensin II receptor density in diabetes mellitus in the rat: time course and mechanism. 354 58

Density and affinity of glomerular angiotensin II (ANG II) receptors were determined in normal, untreated, and insulin-treated streptozotocin-diabetic rats 3-4 wk after the onset of diabetes mellitus. With low, intermediate, and high salt intake, angiotensin II receptor density varied inversely with the plasma renin concentration (PRC) in normal, insulin-treated, and untreated diabetic rats. PRC values with all three dietary regimens were lower in the untreated diabetic rats when compared with the other groups. Despite lower plasma renin concentration, however, untreated diabetic rats were also found to have significantly lower glomerular ANG II receptor concentrations at all levels of salt intake. On a normal salt intake, glomerular ANG II receptor density was reduced significantly in untreated diabetic rats (853 +/- 74 (SE) fmol/mg protein), compared with insulin-treated diabetic rats (1,185 +/- 118 fmol/mg) and normal controls (1,058 +/- 83 fmol/mg). ANG II receptor affinity did not change with alternations in salt intake or degree of diabetic control. Reduced glomerular ANG II receptor density in the presence of a suppressed renin-ANG II axis may underlie the altered renal vascular responsiveness to ANG II known to occur in diabetes mellitus.
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PMID:Reduced glomerular angiotensin II receptor density in early untreated diabetes mellitus in the rat. 633 Nov 95

To determine the effect of diabetes on the cardiac renin-angiotensin system, we compared angiotensin II binding density and renin, angiotensinogen, and type 1 angiotensin II (AT1) receptor mRNA levels in hearts of Sprague-Dawley rats 14 days after the administration of streptozotocin (STZ), in vehicle-treated control rats, and in STZ-administered rats made euglycemic with insulin. Myocardial angiotensin II receptor density, determined using an in situ autoradiographic technique, was increased significantly in hyperglycemic diabetic rats in comparison with control rats and euglycemic diabetic rats (P < 0.01) as a result of an increase in both AT1 and AT2 (type 2 angiotensin II) subtypes. The myocardial AT1 receptor mRNA level, determined by slot blot hybridization, was also significantly greater in the hyperglycemic diabetic rats (P < 0.005). Neither plasma renin concentration nor cardiac renin or angiotensinogen mRNA levels differed among the three study groups. In an additional experiment, control and diabetic rats were infused with angiotensin II (200 ng.kg-1.min-1 i.p. for 7 days) or vehicle. Plasma renin concentration decreased significantly, whereas no significant changes occurred in cardiac renin or angiotensinogen steady-state mRNA levels. As in the first experiment, levels of AT1 receptor mRNA were significantly greater in the diabetic rats. Thus, myocardial angiotensin II receptor density is increased in diabetic rats in association with an increase in steady-state AT1 receptor mRNA levels, an abnormality that appears to be independent of changes in the circulating renin-angiotensin system.
Diabetes 1994 Oct
PMID:The cardiac renin-angiotensin system in STZ-induced diabetes. 792 85

We examined acute and chronic effects of thromboxane (TX) A2 inhibition on the renal hemodynamics at early and late stage of untreated streptozotocin (STZ)-induced diabetic rats. Two weeks and 28 weeks after the induction of diabetes, renal blood flow (RBF) under anesthesia was measured with an electromagnetic flowmeter before and after TXA2 inhibition. In two-week-old diabetic rats, a specific TXA2 synthetase inhibitor, OKY-046, or a specific TXA2 receptor antagonist, Sulotroban, increased renal vascular resistance (RVR) and ameliorated the hyperperfusion. The renal vasoconstrictive effect of OKY-046 was blunted by an angiotensin converting enzyme (ACE) inhibitor, MK422, or an angiotensin II receptor antagonist, Saralasin. On the contrary, OKY-046 ameliorated the renal hypoperfusion by decreasing RVR in 28-week-old diabetic rats. Chronic oral administration of OKY-046 ameliorated not only the renal hyperperfusion but increased urinary albumin excretion (UAE) at two weeks, but also the renal hypoperfusion, filtration fraction and UAE at 24 weeks. It is suggested that TXA2 might, at least in part, play important roles in the hyperperfusion by modulating activity of the renin-angiotensin system at an early stage of untreated diabetic rats and in the hypoperfusion at the late stage of untreated diabetic rats, and that TXA2 is also involved in the increase of UAE. These results support roles for TXA2 in the progression of renal injury in STZ-induced diabetic rats.
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PMID:Acute and chronic effects of thromboxane A2 inhibition on the renal hemodynamics in streptozotocin-induced diabetic rats. 819 81

After a brief synopsis of the classical antihypertensive drugs a survey is given of the newer therapeutics, such as calcium antagonists, ACE-inhibitors and alpha 1-adrenoceptor antagonists. Experimental drugs, such as imidazoline receptor agonists, renin inhibitors, angiotensin II receptor antagonists, alpha 2-adrenoceptor antagonists, potassium channel openers, ketanserin, endopeptidase inhibitors, and hybrid (multifactorial) drugs are discussed, with special attention for their modes of action. In spite of the ever increasing number of antihypertensive drugs and principles, the large scale of clinical evidence for a beneficial effect of long-term treatment (in particular with respect to protection against stroke) remains limited to diuretics and beta-blockers. In spite of this limitation it seems worthwhile to consider the newer antihypertensive drugs as well, especially for optimal treatment of the individual patient. The newer drugs may in particular offer special advantages in the presence of concomitant diseases, such as diabetes mellitus, hyperlipidaemia, angina pectoris or congestive heart failure.
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PMID:New avenues in antihypertensive drug treatment. 826 86

We examined the effect of the angiotensin II receptor blocker, ZD 8731, on nerve function, capillary density, and blood flow in streptozotocin-diabetic rats. Deficits in sciatic motor and saphenous sensory nerve conduction velocity of 21% and 15%, respectively, were observed after 1 month of diabetes mellitus (p < 0.001). These were completely ameliorated by a further month of ZD 8731 treatment (p < 0.001). Treatment of non-diabetic rats for 1 month with ZD 8731 had no effect on motor or sensory conduction velocity. Sciatic nerve capillary density was not significantly affected by 1- or 2-month untreated diabetes, however, there was a 15% increase in density with ZD 8731 treatment (p < 0.001). Treatment of non-diabetic rats for 1 month had no effect on capillary density. Diabetes prolonged the time taken for 80% conduction failure by 19% (p < 0.05) and 49% (p < 0.001) for 1 and 2 months of diabetes, respectively, when sciatic nerve was exposed to hypoxia in vitro. ZD 8731 treatment during the second month of diabetes limited the prolongation to 22%, not significantly different from 1 month of untreated diabetes but less than for the 2-month diabetic group (p < 0.001). Concentrations of sciatic nerve polyol pathway metabolites were elevated six-fold and myo-inositol was reduced 40% by diabetes; ZD 8731 treatment was without effect. Acute experiments examined the effect of ZD 8731 on sciatic nerve blood flow using laser-Doppler flowmetry. In non-diabetic rats, blood flow changes followed the dose-dependent reductions in systemic arterial pressure and there were no significant variations in sciatic vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Angiotensin II receptor blockade improves nerve function, modulates nerve blood flow and stimulates endoneurial angiogenesis in streptozotocin-diabetic rats and nerve function. 830 49

Diabetic nephropathy is the single most common cause of end-stage renal disease in the United States. Recently, several major therapeutic interventions have been developed and demonstrated to slow or halt the progression of renal failure in patients with diabetes and diabetic kidney disease. The Diabetes Control and Complications Trial demonstrated that microalbuminuria developed in fewer patients in the intensive blood sugar control group than in the conventional therapy group. Similarly, the risk of developing proteinuria was reduced by intensive blood sugar control. Multiple studies have demonstrated that in patients with insulin-dependent diabetes and proteinuria, lowering the systemic blood pressure slows the rate of decline in renal function and improves patients' survival. In the recently completed trial of ACE inhibition in diabetic nephropathy, ACE inhibitors were specifically shown to decrease dramatically the risk of doubling of serum creatinine or reaching a combined outcome of end-stage renal disease or death. In studies in small numbers of patients with insulin-dependent diabetes and established diabetic nephropathy, dietary protein restriction has also been demonstrated to slow the rate of decline of renal function. New potential interventions currently undergoing study include the use of aldose reductase inhibitors, the use of drugs that prevent the formation of advanced glycosylation end-products, and the use of angiotensin II receptor antagonists. Thus, several established benefits have recently been demonstrated to help prevent the development of or slow the progression of diabetic nephropathy, including blood pressure control, blood sugar control, and treatment with ACE inhibitors. Dietary protein restriction may also be of benefit. Multiple new interventions are undergoing clinical trials currently.
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PMID:Medical management of nephropathy in type I diabetes mellitus: current recommendations. 874 76

The present study examined vascular reactivity to angiotensin II in blood-perfused kidneys of diabetic normotensive Wistar-Kyoto (WKY) and diabetic spontaneously hypertensive rats (SHR). In addition, the effect of the angiotensin AT1 receptor antagonist, CV-11974 (2-ethoxy-l-[[2'-(1 H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1 H-benzimidazole-7-carboxylic acid), on angiotensin II responses was examined. Dose-response curves to angiotensin II (0.1-30 micrograms/kg, i.a.) were obtained in kidneys of control- and diabetic-WKY rats and -SHR rats, either in the absence or presence of CV-11974 (3 micrograms/kg, i.v.). In all four treatment groups, angiotensin II produced dose-dependent increases in renal perfusion pressure with the order or reactivity: control-SHR > control-WKY = diabetic-SHR > diabetic-WKY. In the presence of CV-11974 (3 micrograms/kg, i.v.), dose-response curves to angiotensin II were significantly inhibited in kidneys of control-SHR and -WKY rats. However, CV-11974 (3 micrograms/kg, i.v.) had no significant effect on angiotensin II responses in kidneys of diabetic-SHR or -WKY rats. These results suggest that diabetes in normotensive rats is associated with impaired renal responsiveness to angiotensin II, while hypertension augments renal responsiveness to angiotensin II. However, the combination of diabetes and hypertension has largely offset the opposite effects on angiotensin II responses seen separately. Importantly, the lack of effect of CV-11974 in diabetic rats, with or without hypertension, has been identified. While the reasons for these alterations have yet to be determined, they may involve changes in angiotensin II receptor mechanisms (e.g. density and/or affinity).
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PMID:Vascular reactivity to angiotensin II in blood-perfused kidneys of hypertensive diabetic rats. 888 15


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