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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neurosecretory terminals (neurosecretosomes, NSS) were isolated from rat neurohypophyses. High [K+]o or veratridine stimulated secretion of vasopressin and oxytocin by up to approximately 100-fold. Stimulated secretion was dependent on calcium and temperature, and could be elicited from NSS maintained in culture for 4 days. After overnight culture of the NSS, secretion was still inhibited by calcium channel blockers (cobalt, dihydropyridines, omega-conotoxin, D 600) and kappa opiates (dynorphin and U50488). Ionomycin evoked dose- and calcium-dependent hormone release, with a Hill coefficient for calcium of 1.74. High [K+]o enhanced the 5 microM ionomycin-induced secretion, apparently through calcium entry rather than depolarization, as the increase in secretion was abolished by 100 microM D 600. During prolonged depolarization the hormone secretion peaked within 2 min, then declined to near basal levels. Depolarization for 25 min without calcium neither activated secretion nor prevented subsequent secretion on readdition of calcium, suggesting that the decline in secretion was not due to membrane depolarization. Indeed, the rates of decline in secretion were similar for different levels of depolarization (0.070 +/- 0.003 and 0.081 +/- 0.003 min-1 for 25 and 45 mM [K+]o, respectively). Four minutes after the onset of continuous depolarization (45 mM [K+]o) in the presence of calcium, the declining secretion was still dependent on voltage-activated calcium influx through channels sensitive to D 600 and nitrendipine. The results presented here suggest that the decline in secretion during prolonged depolarizing stimuli may be due to exhaustion, inactivation, or desensitization of a calcium-triggered event.
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PMID:Activation and inactivation of oxytocin and vasopressin release from isolated nerve endings (neurosecretosomes) of the rat neurohypophysis. 207

Psychological conditions which produce sustained activation have been clearly identified. Among these are the predictability and the controllability of the situation. We studied the impact of these psychological variables on hormone secretion (cortisol, ACTH, vasopressin, prolactin, and hGH plasma levels) under a standardized physical load. Sixteen subjects participated in four sessions each, one week apart, with the task of riding a bicycle until exhaustion. During three sessions, all experimental conditions were held identical to ensure the situation was a predictable as possible. During the fourth session, instructions induced a certain level of uncontrollability. Whereas physiological and performance measures did not vary with experience in the task, cortisol, ACTH, and vasopressin responses declined with increasing experience. This emphasizes the importance of the psychological definition of the situation for endocrine stress responses.
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PMID:Hormonal responses to exhausting physical exercise: the role of predictability and controllability of the situation. 217 35

Children and adults with pyelonephritic renal scarring are at high risk of developing hypertension. The objectives of the present investigation were to study if it is possible to detect early disturbances in blood pressure (BP) control and secretion of hormones involved in the regulation of BP and renal function, in patients with renal scarring. We studied renal function at rest, BP regulating hormones and BP at rest and during graded bicycle exercise until exhaustion. The 22 patients with renal scarring had significantly lower glomerular filtration rate and renal blood flow than the 13 healthy age-matched controls. At rest, the patients had higher diastolic (p less than 0.01) and mean arterial BP (p less than 0.02), higher plasma renin (p = 0.06) and higher serum osmolality (p less than 0.001) but there were no significant differences in systolic BP, angiotensin II, aldosterone or vasopressin (AVP). The patients with renal scarring had higher AVP than the controls during light and moderate exercise and 15 min after maximal exercise. BP and renal hormones increased significantly but similarly during exercise in both patients and controls. There were no significant differences in BP control or release of pressure-regulating hormones at maximal exercise. Maximal exercise did not evoke pathological BP response in normotensive young adults with pyelonephritic renal scarring. The increase in serum osmolality and hypersecretion of AVP during light and moderate exercise may be important in the pathogenesis of hypertension in this group of patients.
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PMID:Altered vasopressin release and osmotic regulation during exercise in patients with pyelonephritic renal scarring. 227 51

The effect of acute exercise on plasma immunoreactive-atrial natriuretic factor (IR-ANF) was studied in 5 healthy young males subjected to graded exercise on a bicycle ergometer at four different work intensities (approx. 30, 50, 70, and 90% VO2max respectively). Except for the final exercise period, which was continued until exhaustion, all the others were of 30 min duration. Venous blood samples were obtained in the last 2 min of each exercise period. The plasma IR-ANF response to exercise was similar to that of heart rate and systolic blood pressure in that mild exercise in the first stage (corresponding to approx. 30% VO2 max) caused a striking increase of plasma IR-ANF concentrations with a further augmentation in the next stages and a levelling off at exhaustion. Plasma arginine-vasopressin (AVP) and aldosterone (ALDO) rose significantly only in the last two stages, and the highest concentrations were observed at exhaustion. In conclusion, acute exercise stimulates ANF secretion in proportion to the intensity of exercise, while concomitant increases in plasma AVP and ALDO occur only when the work load exceeds the blood lactate (BLA) threshold.
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PMID:Effect of acute exercise on plasma immunoreactive-atrial natriuretic factor. 294 77

The growth factors FGF and vasopressin were found to have only a transient effect on confluent quiescent monolayers of Swiss 3T3 cells. Whether measured as cumulative entry into S-phase by autoradiography, or as cell division by time-lapse filming, the elevated rate of cell proliferation was maintained only over 10-15 hr. Several trivial or artifactual explanations for this transience were ruled out, including toxicity of 3H-thymidine; exhaustion or degradation of medium components, nutrients or growth factors (although some medium depletion was observed); and the generation during quiescence of cells incapable of division. We have also eliminated heritable variation in the capacity to respond to individual growth factors. However, unstable phenotypic heterogeneity in growth factor requirements between cells may play some part, as found elsewhere for the response to low concentrations of serum (Brooks et al, 1984). Cell populations that had ceased to respond to vasopressin recovered their sensitivity after 2-3 days' incubation in conditioned medium lacking vasopressin. The phenomenon thus resembles the mitogen-induced desensitization described by Collins and Rosengurt (1982, 1983). However, in our case, the loss of sensitivity was not selective for vasopressin but applied also to epidermal growth factor (EGF) and to prostaglandin F2 alpha. Furthermore, changes in responsiveness to vasopressin with time were associated with changes in cell density. Although some element of selective desensitization has not been ruled out, the transient response in our experiments can be accounted for in terms of unstable heterogeneity in growth factor requirements and/or in terms of density-dependent regulation of growth.
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PMID:Apparent desensitization of Swiss 3T3 cells to the mitogens FGF and vasopressin. 633 90

The effect of intense muscular work (80% of maximal oxygen uptake) on responses of plasma hormones involved in electrolyte and water balance were measured in 14 male subjects. They were divided into three groups according to their maximal oxygen uptake and the duration of exercise performed until exhaustion: well trained subjects (group I), trained subjects (group II), and untrained subjects (group III). Pulmonary gas exchange, heart rate, rectal and skin temperature, and weight loss were measured as well as hematocrit and plasma and urine sodium and potassium concentrations. Rectal temperature increased significantly in all subjects after exhaustion. The variation of hematocrit was smallest and the weight loss greatest in the well-trained subjects. Plasma aldosterone, renin activity (PRA), vasopressin (AVP), and neurophysin (Np) displayed highly significant increases after exercise in all three groups: PRA was increased 4.5 times (p < 0.01), aldosterone 13 times (p < 0.05), Np 2.6 times (p pe 0.05), and AVP 4.8 times (p < 0.05). Nevertheless, there was no correlation between the changes in PRA and those in plasma aldosterone, nor between aldosterone and plasma sodium or potassium. At the urinary level, the only striking observation was that free water clearance tends to become positive after exercise. Our results provide evidence that this kind of exercise produces a highly significant increase in plasma levels of the hormones involved in electrolyte and water balance. They also indicate that it is among the well-trained subjects that sweat loss is highest though the hematocrit increase is the smallest; this suggests that water is shifted more efficiently from the extravascular compartment.
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PMID:Plasma AVP, neurophysin, renin activity, and aldosterone during submaximal exercise performed until exhaustion in trained and untrained men. 699 37

The influence of endurance-training on hematocrit, plasma vasopressin, renin activity, and aldosterone changes at rest and at the end of an exercise performed until exhaustion at a given and constant relative work-load (87% of maximal oxygen uptake) has been studied in four untrained subjects submitted to a 5-month training. At the end of this period, maximal oxygen uptake increased of 15.2% (p less than 0.01). Hematocrit at rest slightly rose after training, and if exercise constantly induced increases in hematocrit before (p less than 0.001) and after training (p less than 0.005), the per cent increase after training was lower than before (p less than 0.05). Comparison between the importance of weight loss and hematocrit variation showed that when untrained subjects become trained the variation of hematocrit after exercise becomes smaller while weight loss is more important (p less than 0.01). Plasma renin activity (PRA), aldosterone (Aldo) and vasopressin (AVP) levels, compared to control values, displayed a significant increase after exercise before as well as after training. Control values remained unchanged after training for aldosterone and AVP, but were significantly lower (p less than 0.05) for PRA. This latter observation could be explained by the change in blood volume induced by exercise.
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PMID:Plasma vasopressin, renin activity, and aldosterone: effect of exercise and training. 701 15

Plasma vasopressin (AVP) and oxytocin (OXT) were determined by radioimmunoassay in healthy young men before, during and after a running exercise until exhaustion. In four of the five test subjects (one subject was underloaded) physical load resulted in a marked increase in plasma AVP with peak values of 11.7 to 57.8 pg/ml at exhaustion. Plasma OXT increased in three test subjects with peak values of 4.5 to 23.9 pg/ml. Within 1 h of recovery, both neuropeptides returned to basal plasma levels. The relationship between plasma AVP and osmolality (p less than 0.001) suggests that changes in osmolality play a dominant role in regulating the secretion of AVP. Besides peripheral effects, the increased levels of AVP and/or OXT during and immediately after the exercise, respectively, might induce a favourable action on the brain function. Determination of plasma AVP and OXT during a day-night cycle in the same test subjects reveals increased AVP levels from 02.00 to 08.00 h as compared to the other time periods chosen (18.00--24.00 h, p less than 0.001; 08.00--16.00 h, p = 0.031). In contrast, OXT does not differ between these time periods but decreased from 08.00 to 16.00 h (p less than 0.01). Accordingly, no correlation exists between both neuropeptides suggesting an independent secretion. It is unclear whether the circadian variations shown are able to influence the neuropeptide response to exercise.
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PMID:Plasma vasopressin and oxytocin in response to exercise and during a day-night cycle in man. 712 45

The hormonal responses to anaesthesia and cardiac surgery were studied in patients undergoing valve or coronary bypass surgery. Marked increases in antidiuretic hormone levels as a result of surgical stress were seen, and were of approximately equal magnitude in both groups. Although both groups also showed marked increases in plasma cortisol levels in response to operations, this response appeared to be relatively blunted in valve surgery patients, especially at the end of operation and in the intensive care unit. This blunted cortisol response may be a manifestation of exhaustion of adrenocortical reserves in valvular surgical patients whose sympathoadrenal system has already been chronically stimulated by a low output state. The important role of the neuroendocrine system in maintaining homeostasis postoperatively has long been recognized; this relative cortisol deficiency may be aetiologically related to poor postoperative recovery in critically ill valvular surgery patients.
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PMID:Cortisol and antidiuretic hormone responses to stress in cardiac surgical patients. 726 Jul 11

This investigation focuses on the hormonal response to electrolyte changes and water loss in patients suffering from heat exhaustion, hospitalized in Muna during Hajj seasons. The concentrations of cortisol, aldosterone, renin (PRA), vasopressin (ADH) parathyroid hormone (PTH), adrenocorticotrophic hormone (ACTH) and growth hormone (GH) were determined in venous blood samples drawn from the patients upon admission, during, and after treatment. Highly elevated PRA mean values (396.77 +/- 88.58-462.18 +/- 106.95 ng.ml-1.h-1) were recorded, with no statistically significant difference between the readings. A similar trend was seen for cortisol (42.92 +/- 4.30-60.20 +/- 11.90 ug/dl). Vasopressin (ADH) showed a highly elevated value upon admission (42.48 +/- 18.82 pg/ml), which decreased to 23.66 +/- 8.27 pg/ml during treatment, and declined further to 7.67, ranging between 4.04 and 11.30 pg/ml, thereafter. Statistically speaking, however, there was no significant difference between these readings. PTH concentration, on the other hand, increased from an initial value of 143.31 +/- 47.64 to 245.90 +/- 107.34 pmol/l after treatment, but again there was no significant difference between the values. ACTH concentrations showed no detectable values throughout this study. The GH concentration was within normal throughout, ranging from 4.42 +/- 0.87 to 5.19 +/- 1.78 ng/ml. Aldosterone concentration was significantly reduced in the patients upon admission, with an initial value of 187.93 +/- 21.41 pg/ml (p < 0.05 as compared to normal mean value). During and after treatment, aldosterone values were still significantly lower than normal mean (152.63 +/- 13.47, p < 0.05; 145.2 +/- 17.55, p < 0.01, respectively), thereby shedding some light on the possible etiology of persistent metabolic acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Physiological studies on heat exhaustion victims among Mecca pilgrims. 764 64


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