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

To investigate the role of the renin-angiotensin-aldosterone system as a cause of hypertension, 20 hypertensive patients with coarctation of the aorta were studied during normal and low sodium intake and after diuresis with flurosemide. Eight patients with essential hypertension and 13 control subjects were similarly studied. Plasma renin activity values in patients with coarctation were similar to those in patients with essential hypertension and in control patients during normal and low sodium diets. However, after the administration of furosemide, plasma renin activity values were significantly higher in the patients with coarctation than in the other two groups (P less than 0.005 and less than 0.01, respectively). The values for urinary aldosterone, plasma volume and extracell fluid volume (bromide space) were increased in patients with coarctation during both normal and low sodium intake. These renin and aldosterone responses and body fluid spaces in patients with coarctation suggest that their hypertension resembles a one-kidney Goldblatt model. The data help to better define the role of the renin-angiotensin-aldosterone system in the hypertension of coarctation and thus may help guide the clinician in therapeutic interventions.
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PMID:Role of the renin-angiotensin-aldosterone system in hypertensive children with coarctation of the aorta. 42 21

1. Infusion of sufficient renin to raise the blood pressure of normal rats to hypertensive levels resulted in increased renin in the arterial wall. 2. Arterial wall renin and renal venous renin were normal in younger spontaneously hypertensive rats, but in older spontaneously hypertensive rats arterial wall renin was significantly increased and renal venous renin was significantly decreased. 3. Arterial wall renin in rats with either acute or chronic two-kidney Goldblatt renal hypertension was significantly increased, whereas circulatory renin was elevated in the former, but depressed in the latter. 4. Arterial wall renin may play a role in the maintenance of acute and chronic renal hypertension and also perhaps of spontaneous hypertension of long duration in older rats.
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PMID:Arterial wall renin and renal venous renin in the hypertensive rat. 47 82

The number of lipid droplets of the renal medullary interstitial cells was registered in 40 rats with "two-kidney Goldblatt hypertension" and in 27 sham operated normotensive controls. A strong degranulation in the unclaimed kidneys was always associated with the malignant course of hypertension, characterized by a disturbance in the sodium and water balance. Giving 2 per cent saline in addition to demineralized water as a drinking fluid the decrease in the number of granules was prevented in most of the malignant cases. Significant changes in the granule count were never registered at a benign course of hypertension. Degranulation of the medullary interstitial cells in the unclamped kidneys does not unequivocally represent the loss of medullary antihypertensive function. It seems to be directly determined by the disturbance of sodium and water balance and indirectly by the hypertension.
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PMID:On the lipid granularity of renomedullary interstitial cells in benign and malignant courses of renal hypertension. 47 21

In two-kidney Goldblatt hypertensive, spontaneously hypertensive, and normotensive control rats the activity of the renin-angiotensin system was tested during variation of sodium balance. Acute, exactly calculable and selective changes of total body sodium were achieved by hemodialyzing the conscious rats using dialysate with either high or low sodium content. The activity of the RAS was evaluated by blood pressure response to AT II blockade (saralasin bolus injection; 25 micrograms/kg b.w., i.v.) and the plasma-renin activity. During sodium depletion blood pressure maintenance became renin-dependent; sodium loading caused a decrease of renin-angiotensin activity in renovascular hypertension. A weak direct correlation between deprssor response to saralasin and the PRA could be established in the different sodium-depleted and -loaded states.
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PMID:Effects of acute hemodialysis-induced changes in sodium balance on the renin-angiotensin system in renovascular and spontaneously hypertensive rats. 52 96

Total exchangeable sodium (Nae) was measured by wholebody counting of 22Na in 1- and 2-kidney Goldblatt rats before, and for 12 weeks after, renal artery clipping. In 1-kidney Goldblatt rats, Nae relative to body weight increased immediately after the clipping procedure and then fell though not to normal levels; from the 10th to the 12th week it again rose rapidly, probably secondary to vascular damage. In 2-kidney Goldblatt rats, Nae relative to body weight increased immediately after the clipping procedure but by the 5th day it was back to normal and remained normal thereafter. Consideration of the values for absolute Nae (i.e. expressed in mmol per rat) casts some doubt on the reality of the sodium 'retention', except in the 1-kidney Goldblatt rats in the later stages of their hypertension. Immediately after surgery temporary loss of weight (presumably mainly affecting fat stores and muscle) probably accounts for much of the rise in Nae relative to body weight.
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PMID:Long-term measurement of total exchangable sodium in one- and two-kidney Golblatt rats. 55

The distribution of cardiac output was determined by 15 micron radioactive microspheres in all the major organs of spontaneous, DOCA/NaCl and one kidney Goldblatt hypertensive rats and compared to normotensive Wistar rats. Although there were alterations in cardiac output distribution which were characteristic of each model of hypertension significant changes were common to all three were an increased distribution to skeletal muscle with decreases to the lungs, spleen and hepatosplanchnic tissues. The results suggest that alterations in peripheral resistance induced by hypertension are of unequal importance in the different vascular beds with certain vascular resistance changes occurring irrespective of the origin of the hypertension.
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PMID:Distribution of cardiac output in different models of hypertension in the conscious rat. 57 Nov 18

Renin activity (RA) in peripheral plasma, as well as in renal cortex and brain (cortex, stem and medulla) homogenates of rats with spontaneous, Goldblatt, NaCl, adrenal-regeneration and neurogenic hypertension was biologically assayed. The results suggest that RA exists not only in the brain of normotensive but of hypertensive rats as well. RA in the medulla is higher than in other brain areas and in the kidney, both in normotensive and in hypertensive rats with the exception of rats with adrenal regeneration and NaCl hypertension. In most of the experimental forms of hypertension (neurogenic, renal, spontaneous) in which RA in the medulla is increased, the role of the brain renin-angiotensin system seems to predominate, while in forms in which renal RA is elevated (adrenal regeneration) the kidney renin system most probably plays a more important role. A definite inverse interrelation between the brain and the kidney renin-angiotensin systems was established. The interrelation between the two renin systems in NaCl hypertension could not be evaluated, since exogenous factors (Na), which interfere with the kidney renin system, play a considerable role in the pathogenesis of NaCl hypertension.
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PMID:Renin activity in the brain, the kidneys and the peripheral plasma or rats with different experimental models of hypertension. 59 8

Using the radioactive microsphere technique, cerebral blood flow (CBF) was measured in six conscious dogs before intervention and again on the 3rd-5th days after inducing hypertension by the one-kidney Goldblatt (1-KGH) procedure. Sham-operated controls were also studied. The normal temporal variability of CBF, as well as the precision of the microsphere technique in measuring CBF were also determined in other normal dogs. A left atrial catheter was used for the microsphere injections (15 micrometer diam spheres) and an aortic catheter was used for cardiac output and blood pressure measurements. On the 3rd-5th days after 1-KGH, mean aortic pressure increased from a control value of 94 +/- 7 mmHg to 135 +/- 20 mmHg (P less than 0.005). CBF did not change significantly from the control flow of 57.1 +/- 7.9 ml/100 g per min. Calculated cerebral vascular resistance increased by 47 percent (P less than 0.025) above the control value. Hence, the early phase of experimental renal hypertension is associated with adequate autoregulation of cerebral blood flow.
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PMID:Autoregulation of cerebral blood flow during early experimental renal hypertension in the conscious dog. 62 73

The results of 2 studies to determine the relationship between hormonal contraceptive (h.c.) use, hypertension, and nephritis are reported. 828 women, 16-50 years of age, were divided into 3 groups. 1 group had never used h.c.s., 1 group was presently using h.c.s., and 1 group had used h.c.s. for the last time more than a year prior to the study. Women 26-35 years of age who were using h.c.s. at the time of the study more often developed hypertension than other groups. The h.c. users who developed hypertension more often had a family history of hypertension or diabetes mellitus, more often had diabetes themselves, and more often suffered from preeclampsia or eclampsia during pregnancy. In a second study, ethinyl estradiol, norethisterone acetate, epsilon aminocapronic acid, desoxycorticosterone acetate, and table salt were administered singly or in combinations to 2 groups of rats. In one group, a Goldblatt-type hypertension was induced with a clamp on the nephric artery. No increase in blood pressure was observed in animals which received only an estrogenic or progestagenic agent. Significant increases in blood pressure were observed in animals that were given combinations of estrogenic and progestagenic agents, however. Significantly increased plasma-resin activity was observed in all animals which were given estrogen, while animals receiving desoxycorticosterone acetate showed a highly significant decrease in plasma-renin activity.
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PMID:[Oral contraceptives, hypertension and nephrosclerosis]. 62 80

The effect of total adrenalectomy on the mechanisms of arterial pressure control was studied in uninephrectomized rats with and without renal artery stenosis (Goldblatt one-kidney model). Four groups of rats were prepared and maintained on high-salt intake (1% NaCl): uninephrectomized-KI; KI + adrenalectomy-KIAx; uninephrectomized with renal artery stenosis-GI; and GI with adrenalectomy-GIAx. Over 3 wk blood pressure rose significantly in both GI and GIAx but the degree of increase in GI was greater. Hyponatremia, hyperkalemia, and increased plasma urea nitrogen were observed in both KIAx and GIAx. Plasma renin concentration (PRC) and plasma renine activity (PRA) were markedly increased and plasma renin substrate (PRS) was decreased in both adrenalectomized groups. Infusion of saralasin resulted in significant and similar reductions in mean arterial pressure (MAP) in KIAx and GIAx, but had no effect on MAP in KI and GI. These results allow approximations of the contribution to total MAP of identifiable components, which are: the total adrenal component, the renin-angiotensin system component, which partially compensates for loss of the adrenal secretions, and the independent effect of the renal artery clip. Thus, a multifactorial analysis of GI hypertension is provided.
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PMID:Adrenal gland in experimental renal hypertension. 62 42


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