Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.15 (renin)
 35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effects of acute, short-lasting haemorrhage have been studied in six goats. The experiments were made 55 +/- 3 days (mid-pregnancy = MP), and 24 +/- 2 days (late pregnancy = LP) before parturition, in lactation weeks 3-8, and in the non-pregnant, non-lactating (= control) period. The room temperature was kept at 20 +/- 1 degrees C, except during one experimental series in lactating goats, which was performed at +30 degrees C. Approximately the same volume of blood had been removed in all periods, when the mean arterial blood pressure (MAP) fell. At this moment bleeding was stopped. The volume loss, calculated as per cent of total blood volume, was significantly smaller during pregnancy and lactation than in the control period. The fastest heart rate, both at rest and during haemorrhage, was observed in LP goats. The respiratory frequency of the LP goats increased markedly in response to haemorrhage, but the most rapid respiratory rate was observed in lactating goats bled at the room temperature +30 degrees C. The increase in plasma vasopressin (AVP) concentration coincided with the fall in MAP. The AVP rise seen during late pregnancy was significantly higher than in all the other periods. The plasma noradrenaline (NA) concentration increased by about five times in LP goats, but did not change significantly in the other periods. Plasma renin activity did not rise, with the exception of a small increase in lactating goats bled at +30 degrees C. The plasma aldosterone concentration rose, but there was no difference between periods.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of acute haemorrhagic hypotension during pregnancy and lactation in conscious goats. 359 70

The effect of vasopressin released during Finnish sauna on blood pressure, heart rate and skin blood flow was investigated in 12 healthy volunteers. Exposure to the hot air decrease body weight by 0.6 to 1.25 kg (mean = 0.8 kg, P less than 0.001). One hour after the end of the sauna sessions, plasma vasopressin was higher (1.7 +/- 0.2 pg/ml, P less than 0.01 mean +/- SEM) than before the sauna (1.0 +/- 0.1 pg/ml). No simultaneous change in plasma osmolality, plasma renin activity, plasma norepinephrine, epinephrine, cortisol, aldosterone, beta-endorphin and metenkephalin levels was observed. Despite the slight sauna-induced elevation in circulating vasopressin, intravenous injection of the specific vascular vasopressin antagonist d(CH2)5Tyr(Me)AVP (5 micrograms/kg) 1 h after the sauna had no effect on blood pressure, heart rate or skin blood flow. These data suggest that vasopressin released into the circulation during a sauna session reaches concentrations which are not high enough to interfere directly with vascular tone.
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PMID:Haemodynamic role of vasopressin released during Finnish sauna. 375 60

Although the protein components of the renin-angiotensin system have been localized in the brain, it remains to be established whether or not angiotensin II (Ang II) is generated locally and secreted into the interstitial fluid of the brain. We have addressed this issue in vitro by perifusing explants of the rat hypothalamo-neurohypophysial system (HNS) (5 explants per chamber, 37 degrees C) with Krebs solution at a rate of 1 ml/min. The release of Ang II immunoreactivity (Ang II-ir) and arginine vasopressin immunoreactivity (AVP-ir) in the medium was measured 3-5 h after HNS dissection and again after addition of potassium (K+) to the perifusate. Samples of the fluid perifusing the HNS were collected for 30-min intervals and concentrated using Sep-Pak C18 cartridges. Release of Ang II-ir was significantly increased during perifusion with 70 mM K+ (from 29 +/- 14 pg/30 min to 80 +/- 17 pg/30 min, P less than 0.01). This increase coincided with a dramatic rise in the release of AVP-ir (from 50 +/- 35 pg/30 min to values above 2000 pg/30 min). The associated release of Ang II-ir in response to depolarization by K+ is consistent with the hypothesis that Ang II can be secreted by neuronal elements of the brain, possibly via a regulated pathway.
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PMID:Basal and potassium-evoked release of angiotensin II from the rat hypothalamus. 380 61

The effect of maximal treadmill exercise on plasma concentrations of vasopressin (AVP); renin activity (PRA); and aldosterone (ALDO) was studied in nine female college basketball players before and after a 5-month basketball season. Pre-season plasma AVP increased (p less than 0.05) from a pre-exercise concentration of 3.8 +/- 0.5 to 15.8 +/- 4.8 pg X ml-1 following exercise. Post-season, the pre-exercise plasma AVP level averaged 1.5 +/- 0.5 pg X ml-1 and increased to 16.7 +/- 5.9 pg X ml-1 after the exercise test. PRA increased (p less than 0.05) from a pre-exercise value of 1.6 +/- 0.6 to 6.8 +/- 1.7 ngAI X ml-1 X hr-1 5 min after the end of exercise during the pre-season test. In the post-season, the pre-exercise PRA was comparable (2.4 +/- 0.6 ngAI X ml- X hr-1), as was the elevation found after maximal exercise (8.3 +/- 1.9 ngAI X ml- X hr-1). Pre-season plasma ALDO increased (p less than 0.05) from 102.9 +/- 30.8 pg X ml-1 in the pre-exercise period to 453.8 +/- 54.8 pg X ml-1 after the exercise test. In the post-season the values were 108.9 +/- 19.4 and 365.9 +/- 64.4 pg X ml-1, respectively. Thus, maximal exercise in females produced significant increases in plasma AVP, renin activity, and ALDO that are comparable to those reported previously for male subjects. Moreover, this response is remarkably reproducible as demonstrated by the results of the two tests performed 5 months apart.
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PMID:Plasma vasopressin, renin activity, and aldosterone responses to maximal exercise in active college females. 390 94

Osmoregulation during pregnancy was compared in Brattleboro rats completely lacking vasopressin [homozygous (DI)], those with partial deficiency [heterozygous (HZ)], and control Long-Evans (LE) animals. Plasma osmolality (Posmol) was decreased 10-16 mosmol/kg near term in each group, whereas urine osmolality (Uosmol) was similar to that of virgin controls. This was accompanied by significant increments in water turnover similar in HZ and LE and massive in the gravid DI. Chronic vasopressin treatment increased Uosmol less in pregnant DI compared with virgins (P less than 0.001), and urinary prostaglandin E2 was increased in all gravid groups. Captopril per os failed to implicate the renin-angiotensin system in the altered water ingestive behavior of pregnancy. Basal arginine vasopressin pressure (PAVP) was similar in gravid and virgin HZ and LE, whereas the osmotic threshold for AVP secretion was lower in both pregnant groups. Increasing Posmol by dehydration or hypertonic saline led to similar increments in plasma AVP (PAVP) in pregnant and nongravid rats of each group, but sensitivity of the system delta P AVP/delta P osmol was significantly lower in HZ, a difference compatible with the decreased pituitary AVP content in the HZ strain. Data are consistent with decreases in the osmotic thresholds for AVP release (in HZ and LE) and thirst (in DI) and a need for increased AVP secretion during pregnancy.
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PMID:Osmoregulation and vasopressin secretion during pregnancy in Brattleboro rats. 397 Jan 84

Biochemical, cytochemical and immunological methods were used to compare the metabolic and neuroendocrine properties of the subfornical organ (SFO) with the hypothalamo-neurohypophysial system (HNS) in the rat. The SFO resembles the HNS in that both have (a) increased label incorporation into RNA during dehydration; (b) an intense reaction for glucose-6-phosphate dehydrogenase; (c) NADPH-diaphorase and the Type I pathway for hydrogen utilization from NADPH, presumably as part of the mixed-function oxidase system for the metabolism of endogenous substrates and xenobiotics; (d) immunoreactive vasopressin and oxytocin. Gel filtration of extracts of the SFO area using Sephadex G-25 chromatography resulted in immunoreactive peaks for both AVP and OT which were similar to synthetic hormones. One other fraction in the SFO extract, containing a substance(s) of higher molecular weight than AVP, was detected using the antiserum for AVP. The concentration of immunoreactive AVP in the SFO area was increased after colchicine, decreased by hypophysectomy, and unaltered by: (a) infusion (4.6 pg/min for 3 hr) or injection (1 or 6 ng) of AVP into the lateral cerebroventricle; (b) dehydration; (c) renin administered intracerebroventricularly; (d) pinealectomy; or (e) hypertension in the spontaneously hypertensive rat. In conclusion, cells in the SFO have specialized metabolic and neuroendocrine properties similar to the HNS. It can be inferred from these biochemical specializations that the SFO has metabolic and secretory activities.
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PMID:The subfornical organ: biochemical and neuroendocrine comparisons with the hypothalamo-neurohypophysial system. 402 8

Renal plasma flow, glomerular filtration rate plasma angiotensin II, aldosterone and arginine vasopressin, free water clearance, blood pressure and body weight in 11 patients with mild to moderate hypertension were determined at the end of consecutive 6 week periods of administration of placebo and verapamil up to 120 mg t.i.d. Verapamil induced a 10% reduction in diastolic blood pressure. Compared with placebo none of the other parameters measured changed after treatment with verapamil. There was no significant correlation between blood pressure and arginine vasopressin in plasma. It is concluded that verapamil reduced blood pressure by vasodilatation without activation of the counterbalancing mechanisms commonly seen after treatment with vasodilating drugs, i.e. tachycardia, activation of the renin-angiotensin-aldosterone system, water and salt retention, and without affecting renal haemodynamics. AVP does not seem to be involved in blood pressure regulation in mild to moderate essential hypertension.
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PMID:Effect of verapamil on renal plasma flow, glomerular filtration rate and plasma angiotensin II, aldosterone and arginine vasopressin in essential hypertension. 407 25

Collagenase dispersion of rabbit kidney cortex followed by centrifugation on discontinuous sucrose gradient, allowed the simultaneous obtention of microvascular, glomerular and tubular fractions. Microscopic studies and the measurements of cellular renin activity and the muscle-specific-enzyme creatine kinase showed that these vessels were arteriolar in nature and that they contained the preglomerular arterioles. The glomerular or tubular contamination rates were assessed by means of enzymatic markers. AVP stimulated only the tubular fraction whether GTP was present or not. In the absence of GTP, beta-isoproterenol stimulated only the tubular enzyme while in the presence of GTP, the microvascular and especially the glomerular AC were also stimulated. GTP enhanced considerably the microvascular response to bPTH-(1-34) while, in the glomeruli and tubules the effects of GTP and hormones were only additive. The possible physiological significance of these results are discussed.
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PMID:[Distribution of various sites of hormonal action between microvessels, glomeruli and tubules isolated from the renal cortex of rabbits]. 608 66

We have assessed the influence of acute bilateral nephrectomy, of captopril and saralasin, on the hypotensive activity of neurotensin (NT) and of various hypotensive drugs in pentobarbital-anesthetized rats. The results show that the hypotensive activity of NT and of compound 48/80 (C48/80), in contrast to that of histamine, of 5-hydroxytryptamine and of hexamethonium, is markedly reduced, especially for NT, in nephrectomized as compared to sham operated rats. The pretreatment of rats with captopril (10 mg kg-1, i.v.) or with saralasin (20 micrograms kg-1 min-1, i.v.) was found to inhibit significantly the hypotensive activity of NT and of C48/80. Adrenalectomy restored partially the hypotensive activity of NT in nephrectomized rats. The potent vasopressin antagonist [d(CH2)5 Tyr(Me)AVP] did not alter the refractoriness of nephrectomized rats to the hypotensive activity of NT. Neither nephrectomy nor saralasin were found to interfere with the ability of NT or of C48/80 to evoke an increase of plasma histamine level or of the hematocrit. The results were interpreted as an indication that NT produces part of its hypotensive effect in anesthetized rats by reducing the activity of the renin angiotensin system. The results also suggest that part of the refractoriness of nephrectomized rats to the hypotensive activity of NT could be due to the release of catecholamines from adrenal glands by NT. Endogenous vasopressin does not appear to contribute to the refractoriness of nephrectomized rats to the hypotensive action of NT.
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PMID:Partial blockade of neurotensin-induced hypotension in rats by nephrectomy captopril and saralasin. Possible mechanisms. 619 Dec 40

The aim of this study was to assess the influence of hormones known to regulate fluid and electrolyte balance on the release of antidiuretic hormone induced by raising serum osmolality. The stimulus provoked by the infusion of a 2.5% NaCl solution induces an increase of urinary [arginine-8]-vasopressin from 1.12 to 2.64 ng/h in men and from 1.65 to 7.27 ng/h in women as has been previously reported. These results were compared to those obtained in males infused with angiotensin II (AII) before and during a hypertonic sodium load and in males infused with hypertonic saline on the fourth day of administration of ethinyl-oestradiol. During the combined infusion of AII and then hypertonic saline, the mean hourly urinary excretion of AVP increased from 2.8 to 5.67 ng/h. Within each group the increase of urinary AVP was highly significant. The rise of urinary AVP during AII infusion was significantly different from the rise observed both in untreated males and untreated females, lying in between. The mean hourly excretion rate of AVP increased before and after hypertonic saline loading from 2.65 to 5.3 ng/h in males pre-treated with ethinyl-oestradiol. The significant difference observed between males and females is reduced when males treated with oestrogen were compared to female subjects. In each group plasma renin activity decreased to low values during the salt-loading test. During oestrogen treatment PRA and plasma renin substrate rose, while urinary aldosterone remained almost unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Studies of the factors modulating antidiuretic hormone excretion in man in response to the osmolar stimulus: effects of oestrogen and angiotensin II. 635 44


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