ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SUMMARY A protein fraction has been isolated from normal human urine which upon chronic administration produced hypertension in rats. The hypertension is associated with retention of sodium and increased circulating aldosterone. The protein fraction has been purified to homogeneity, and its molecular weight has been determined to be 26,134 daltons by equilibrium ultracentrifugation. The compound has been identified to be clearly different from ACTH, angiotensin II, and β-lipotropin. It stimulated aldosterone production from rat glomerulosa cells in vitro in a dose-dependent fashion from 10" to 10−9to 10−4M with a maximum stimulation at 10−7where a fourfold increase was obtained during 2 hours of incubation. Removal of some carbohydrate moieties by insoluble neuraminidase caused a twofold increase in aldosterone production in vitro. The protein fraction has been named "aldosterone-stimulating factor" or "ASF." Further studies are in progress to define its physiological role.

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SUMMARY We have assessed the influence of a mild emotional stimulus on arterial blood pressure, heart rate, renal blood flow, plasma resin activity (PRA), and plasma aldosterone concentration in 24 normal subjects, eight of whom had a parent with hypertension, and in IS patients with essential hypertension. A nonverbal IQ test, Raven's Progressive Matrices, was employed as the stimulus. In 11 of the 15 hypertensives, arterial blood pressure rose transiently by 7 mm Hg or more, but in only three of 16 normal subjects (x2= 7.23,p< 0.01). Transient moderate increases in heart rate were also more common in the hypertensives (p< 0.01). Renal blood flow rose in 11 of 16 normal subjects and fell in each of the 15 patients with essential hypertension (x* − 15.1;/> < 0.005). As opposed to the transient changes in arterial pressure and heart rate, the fall in renal perfusion was sustained. The PRA fell in 10 of the 16 normal subjects with a negative family history and rose In 14 of 15 patients with essential hypertension (p< 0.005). Changes in plasma angiotensin II concentration and in plasma aldosterone were in accord with the changes in PRA, but plasma cortisol did not change. Both the renal vascular response and the change in PRA were intermediate in normal subjects in whom family history was positive for hypertension. For the entire group of 39 subjects there was statistically significant agreement between the direction of the renal vascular response and the directional change in PRA: renal blood flow rose when PRA fell and fell when PRA rose (p< 0.005). We conclude that there is an abnormality in the control of both the renal circulation and of renin release in patients with essential hypertension in response to psychological provocation, and that a similar process is present in some normotensive subjects whose parents have hypertension.

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SUMMARY The role of kinins in the acute antihypertensive effect of a converting enzyme inhibitor (CEI) was studied in sodium-depleted normotensive and in two-kidney, one clip chronically hypertensive rats (2K- 1C). The 2K-1C were on a normal sodium diet. The acute vasodepressor effect of the CEI was determined in these two groups either after administration of normal rabbit globulins or antikinin globulins. The amount of kinin antibodies administered completely blocked the hypotensive effects of bradykinin, 400 ng/kg, and urinary kallikrein, 4 $Mg/kg- After administration of CEI in the sodium-depleted rats there was no significant difference (p > 0.05) in the acute changes in mean blood pressure (BP) between the group pretreated with normal rabbit globulins (ABP Δ32.3 ± 3.9 mm Hg) and the group pretreated with antikinin globulins (ABP Δ25 ± 2.5 mm Hg). In the 2K-1C pretreated with normal rabbit globulins, the CEI produced a decrease in BP of −21 ± 4.5 mm Hg. This decrease was almost completely blocked in the group pretreated with the antikinin globulins (ABP Δ4 ± 4.1 mm Hg). These differences in the changes in BP were significant (p< 0.02). These results suggest that the acute antihypertensive effect of the CEI in the sodium-depleted rats is probably due to inhibition of the conversion of angiotensin I to II while in the 2K-1C it is due, in part, to an increase in kinin concentrations secondary to the inhibition of kininase II.

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SUMMARY The effects of propranolol on angiotensin II (AH) enhancement of sympathetic nerve transmission were investigated in the in situ blood-perfused mesenteric vascular bed of the rat. Angiotensin II in subpressor concentrations (3 ng/ml) potentiated the vasoconstrictor responses to both sympathetic nerve stimulation (NS) and exogenous norepinephrine (NE). The dl-propranolol had no effect on the basal vasoconstrictor responses to NS and NE, yet inhibited the All-enhanced vasoconstrictor responses to NS by 47% (p< 0.0S) and 81% (p< 0.001) at 100 and 300 ng/ml respectively. In contrast, the potentiation of NE responses by AH was unaffected by propranolol. A similar blockade of All enhancement of NS was observed with the d-isomer of propranolol. Dibucaine (300 ng/ml), a local anesthetic, failed to alter the basal or AH-enhanced responses to either NS or NE. Indomethacin, a prostaglandin synthetase inhibitor (5 mg/kg, s.c), abolished the inhibitory effect of dl-propranolol on AH enhancement of NS. Prostaglandin Ej (PGE,), but not prostaglandin Ii. (3 ng/ml) inhibited AH enhancement of NS without altering the basal response to NS or NE in indomethacin-pretreated animals. Intraarterial infusions of dl-propranolol, d-propranolol, AH, and dlpropranolol-plus-AII into the superior mesenteric artery increased mesenteric venous PGE, concentrations from 216 ± 33 to 355 i 33 (p< 0.01), 328 ± 44 (p< 0.05), 325 ± 27 (p< 0.02), and 407 ± 44 pg/ml (p< 0.01) respectively. We conclude that propranolol antagonizes AH enhancement of NS by increasing prostaglandin levels in vascular tissue. Furthermore, these findings suggest that propranolol may exert its antihypertensive effect through the release of prostaglandins when used in therapeutic doses in excess of those required for beta-adrenergic blockade.

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SUMMARY To determine the role of vasopressin in the maintenance of high blood pressure, the antihypertensive effect of the antagonists of the vasopressor effect of vasopressin, [l-deaminopenicillamine, 4- valine, 8-D-arginine] vasopressin (dPVDAVP), and [l-(β-mercapto-β, β-cyclopentamethylenepropionic acid), 4-valine, 8-D-arginine] vasopressin (cyclo dVDAVP), was studied in unanestfaetized, nonsurgically stressed rats with adrenal regeneration hypertension, malignant DOCA-salt hypertension, and malignant twokidney, one clip Goldblatt hypertension. The doses of vasopressin antagonist used blocked the blood pressure (BP) response to vasopressin almost completely, with no changes in the pressor response to norepinephrine and angiotensln II. Administration of the vasopressin antagonists did not induce significant changes in the mean BP in any of the three experimental groups studied. It is suggested that in unanesthetized, nonsurgically stressed rats with adrenal regeneration hypertension, malignant DOCA-salt hypertension, and malignant two-kidney, one clip Goldblatt hypertension, vasopressin does not have a role in the maintenance of high BP.

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SUMMARY This study reviews the blood pressure (BP) determinations previously recorded in a primary care center serving a low socioeconomic population and compares the systolic blood pressure (SBP) and diastolic blood pressure (DBP) distributions within the clinic population among the three major ethnic groups represented, and also between this clinic population and a recently reported standard population (Task Force for Blood Pressure Control in Children, NHLBI). The study group consisted of 2810 children 3-17 years of age, of whom 49.2% were of Spanish surname, 23.4% black, and 27.4% white. As a standard clinic procedure, BP readings were obtained from the right arm with the subject seated.Comparisons of the average SBP by 3-year age groups, by sex, within the clinic population showed that blacks had higher SBPs than children with Spanish surnames or whites in all of the five male subgroups and in four of the five female subgroups. Black males had higher DBPs than Spanish or whites in four of the five subgroups; black females had higher DBPs hi three of the fire subgroups.SIn comparison with the standard population, the overall 95th percentile values for both SBP and DBP were lower. The prevalence of readings above the 95th percentile values reported for the standard population over all age groups was as follows: SBP, 1.53%; DBP, 1.60%; and both SBP and DBP, 0.57%. Proportionately, elevated readings were most common among blacks and least common among whites. However, these differences between ethnic groups could be accounted for statistically, to a great extent, by adjusting for height and weight, since blacks were the tallest and heaviest of the three groups. The results suggest that, even in childhood, blacks presenting at a primary care center have higher BPs than Spanish or whites, but that this difference is largely related to body size.

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SUMMARY Of 32 studies comparing plasma norepinephrine concentrations in hypertensive and normotensive groups, 28 (88%) reported higher levels in the hypertensive group. However, only 13 (41%) of the studies reported statistically significant hypertensive-nonnotensive differences in norepinephrine, leading the present attempt to identify factors differentiating "positive" studies (those reporting significant hypertensivenormotensive differences) from "negative" studies (those reporting nonsignificant differences). Hypertensive norepinephrine levels were similar in positive and negative studies (281 vs 288 pg/ml), but normotensive levels were lower in the positive studies (177 vs 269 pg/ml). When compared with the fluorimetric technique, the radioenzymatic type of assay was associated both with a lower frequency of positive results (25% vs 100%) and greater intrastudy standard deviations (152 vs 72 pg/ml). Hypertensive-normotensive differences varied inversely with age (> = &#151;0.37). Resolution of the persisting controversy about norepinephrine levels in essential hypertension will require more attention to the causes of variability associated with the assay technique, to the sources, characteristics, and treatment of the normotensive controls, and to the age of the patient population.

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SUMMARY The case is reported of a young woman with severe hypertension, unilateral renal artery stenosis, variously normal or marginally high plasma concentrations of active renin, angiotensin II, aldosterone, sodium, and potassium; and normal total exchangeable and total body sodium and potassium. Arteriograms and ureter catheterization showed the stenosis to be severe, but the unstimulated renal vein renin and angiotensin II differential to be modest. Captopril caused an initial fall in angiotensin II and arterial pressure. During prolonged captopril treatment, plasma angiotensin II and aldosterone remained depressed; exchangeable and total body sodium and potassium were unaltered. Blood pressure fell further to normal levels during prolonged captopril treatment, while subsequent surgical correction of the renal artery stenosis was curative; absolute values of blood pressure and plasma angiotensin II were similar in both situations. The findings support, without proving, the concept that chronic modest elevation of angiotensin II may be responsible for sustained hypertension in unilateral renal artery stenosis. Patients of this type contrast sharply with those, also with severe renal artery stenosis or occlusion, who have gross elevation of renin, angiotensin II, and aldosterone, with sodium and potassium deficiency. Captopril or surgery are effective in both syndromes, but the manner of response to treatment differs markedly.

ISSN:0194-911X    

出版商:OVID    

年代:1981

数据来源: OVID