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Query: UMLS:C0392674 (exhaustion)
 13,658 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment of unanesthetized castrated adult male rats every 3 h for 48 h with either 5 microgram of arginine vasotocin (AVT) and/or 1 microgram luteinizing hormone-releasing hormone (LRH) caused a significant inhibition of plasma levels of luteinizing hormone (LH) and compared to castrated control rats receiving diluent only. However, the intravenous (iv) injection of 1 microgram of AVT into urethane-anesthetized male rats which had been castrated for 0, 24 or 48 h did not affect plasma levels of LH at 10, 20 or 60 min following injection compared to their respective diluent-treated castrated control rats. Similarly, the iv injection of either 100 ng, 1 microgram or 10 microgram AVT was unable to acutely affect plasma levels of LH in intact male rats. Following the iv injection of 2 doses of 50 ng LRH spaced 1 h apart in anesthetized castrated male rats, 2 peaks of equal magnitude in plasma LH were noted. Castrated rats treated with 2 injections spaced 1 h apart of LRH + AVT had significantly higher plasma levels of LH than did rats treated with LRH alone. In subsequent studies, both AVT and arginine vasopressin were observed to augment the plasma response of LH to an injection of LRH whereas oxytocin had no effect. A single injection of AVT + LRH significantly augmented the plasma titers of LH compared to levels observed in LRH-treated control rats as did a second injection 1 h later. The administration of cyproterone acetate sc for 2 days by itself had no effect on plasma LH but in conjunction with LRH caused a marked rise in plasma LH compared to intact rats treated with LRH alone. AVT in combination with LRH and cyproterone acetate caused a significant elevation in plasma LH at 60 min post-injection when compared to plasma levels of rats treated with LRH alone or the combination of LRH and cyproterone acetate. It is concluded that acute intravenous injections of AVT augment the LH-releasing activity of LRH; chronic treatment for 48 h, however, with LRH + AVT leads to a significant depression of plasma LH perhaps due to an exhaustion of the releasable pool of LH in the anterior pituitary.
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PMID:Interaction of luteinizing hormone-releasing hormone, cyproterone acetate and arginine vasotocin on plasma levels of luteinizing hormone in intact and castrated adult male rats. 37 36

The influence of moderate cold exposure on the hormonal responses of atrial natriuretic factor (ANF), arginine vasopressin (AVP), catecholamines, and plasma renin activity (PRA) after exhaustive exercise was studied in 9 young and 10 middle-aged subjects. Exercise tests were randomly performed in temperate (30 degrees C) and cold (10 degrees C) environments. Heart rate, oxygen consumption, and peripheral arterial blood pressure were measured at regular intervals. Blood samples were collected before and immediately after exercise at 30 or 10 degrees C. Plasma sodium and potassium concentrations as well as hemoglobin and hematocrit were measured, and the change in plasma volume was calculated. At rest and during exercise, oxygen consumption was similar during exposure to both temperate and cold temperatures. During submaximal exercise intensities, the rise in heart rate was blunted while the increase in systolic blood pressure was significantly greater at 10 than at 30 degrees C. The increases in plasma sodium and potassium concentrations after exhaustion were similar between environments, as was the decrease in plasma volume. In both groups, all plasma hormones were significantly elevated postexercise, with the AVP response similar at 10 and 30 degrees C. However, the norepinephrine and ANF responses were significantly greater while the PRA response was significantly reduced at 10 degrees C. In the middle-aged subjects the epinephrine response to exercise was higher at 10 than at 30 degrees C. The greater ANF and reduced PRA responses to exercise in the cold may have resulted from central hemodynamic changes caused by cold-induced cutaneous vasoconstriction.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hormonal responses to exercise during moderate cold exposure in young vs. middle-age subjects. 144 5

Plasma renin activity and plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin (AVP) and aldosterone (Aldo) were determined in six physically conditioned male volunteers and five unconditioned volunteers who served as controls. All volunteers were subjected to acute exercise for 15 min or until exhaustion. In the conditioned volunteers, the plasma concentrations of all hormones did not change when compared with pre-exercise values measured immediately after and 60 min after exercise. Similarly, plasma renin activity (PRA) after exercise was unchanged when compared with pre-exercise levels. In contrast, the unconditioned volunteers showed elevation of the plasma concentrations of AVP, and Aldo. PRA also increased in the unconditioned volunteers, but plasma ANP concentrations were not significantly different from base-line pre-exercise levels. These data suggest a decrease in central volume with exercise in the unconditioned individuals, which probably does not occur in the conditioned individual because of adaptive mechanisms. The data also suggest that in the physically conditioned individual, significant atrial distention with resultant release of atrial natriuretic peptide does not occur, or alternatively, that significant atrial distention in these subjects fails to produce the expected release of atrial natriuretic peptide. In the unconditioned individual, the postulated decrease in effective central volume following exercise would not be expected to trigger any rise in ANP.
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PMID:Concentrations of volume-regulatory hormones after acute exercise in physically conditioned males. 207 51

The physiological mechanism of exercise-induced hyperfibrinolysis is not fully understood. It has been reported that exercise increases plasma arginine vasopressin (PAVP) and that PAVP infusion enhances blood fibrinolytic activity (FA). To characterize the fibrinolytic role of PAVP during exercise, PAVP and FA were examined before and after submaximal and maximal exercise in 16 normal, healthy volunteers. After completion of a 100% VO2max exercise test on a bicycle ergometer, which elicited exhaustion in 14.3 +/- 1.4 min (MSD), subjects were randomly assigned to exercise trials at 40% and 70% VO2max for 15 min, each of the three tests being separated by 7 d. Prior to and immediately after the completion of the respective exercise treatment, heart rate, VO2 uptake, and respiratory quotient were measured and venous blood was removed and analyzed for PAVP using radioimmunoassay. The fibrin plate method (FP) and euglobulin lysis time (ELT) technique were employed to assess FA. The intrinsic and extrinsic plasminogen activators' response to all exercise treatments was also examined in pooled plasma prepared from the same subjects. Differentiation between the intrinsic and extrinsic activators' activity was ascertained in the FP by blocking the former with the addition of C1-inactivator. Lactic acid was measured using a standard spectrophotometric method. Compared to rest, FA was significantly increased (P less than 0.05) in all exercise tests when assessed using ELT, with a response related to exercise intensity. However, the 40% VO2max exercise trial caused a nonsignificant increase (P greater than 0.05) in FA using the FP method, with a significant increase (P less than 0.05) being observed in 70% and 100% VO2max exercise tests.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Exercise intensity-related responses of fibrinolytic activity and vasopressin in man. 240 10

The effects of acute exercise on plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), and plasma renin activity (PRA) were studied in 13 patients with previously untreated essential hypertension, and 8 matched normotensive control subjects. Resting levels of ANP and PRA were similar in the two groups, while resting AVP concentrations were 1.4 times higher in hypertensive subjects. Graded exercise was performed on a bicycle ergometer with workload increased each minute until exhaustion (Wmax). Wmax was higher in normal subjects than in hypertensive patients. Blood pressure and heart rate rose more steeply in hypertensive patients. Plasma ANP increased during acute exercise in both groups, but the average increase in hypertensives was substantially greater than in normal subjects (P less than 0.05). The increase in ANP during exercise was greater in hypertensives with left ventricular (LV) hypertrophy, and there was a positive correlation between LV mass and the percentage rise in ANP during exercise (r = 0.56, P less than 0.005). Plasma AVP did not alter during exercise. Plasma renin concentrations showed a small rise during exercise in both groups, which was 16% less in hypertensive subjects (P less than 0.05). The enhancement of ANP release during exercise in hypertensive subjects may reflect both cardiac structural changes and increased redistribution of blood to the cardiopulmonary compartment.
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PMID:Exaggerated atrial natriuretic peptide release during acute exercise in essential hypertension. 297 6

We wished to determine whether the increased ACTH during prolonged exercise was associated with changes in peripheral corticotropin-releasing hormone (CRH) and/or arginine vasopressin (AVP). Six male triathletes were studied during exercise: 1 h at 70% maximal oxygen consumption, followed by progressively increasing work rates until exhaustion. Data obtained during the exercise session were compared with a nonexercise control session. Venous blood was sampled over a 2-h period for cortisol, ACTH, CRH, AVP, renin, glucose, and plasma osmolality. There were significant increases by ANOVA on log-transformed data in plasma cortisol (P = 0.002), ACTH (P < 0.001), CRH (P < 0.001), and AVP (P < 0.03) during exercise compared with the control day. A variable increase in AVP was observed after the period of high-intensity exercise. Plasma osmolality rose with exercise (P < 0.001) and was related to plasma AVP during submaximal exercise (P < 0.03) but not with the inclusion of data that followed the high-intensity exercise. This indicated an additional stimulus to the secretion of AVP. The mechanism by which ACTH secretion occurs during exercise involves both CRH and AVP. We hypothesize that high-intensity exercise favors AVP release and that prolonged duration favors CRH release.
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PMID:Prolonged exercise increases peripheral plasma ACTH, CRH, and AVP in male athletes. 972 55

The growth hormone (GH), cortisol, and arginine vasopressin (AVP) responses to bicycle ergometry (with increasing workload until exhaustion) were measured in 20 patients affected by insulin-dependent diabetes mellitus (IDDM) (10 habitual smokers and 10 nonsmokers) and 20 nondiabetic subjects (normal controls) (10 habitual smokers and 10 nonsmokers). Cardiorespiratory parameters such as heart rate, blood pressure, ventilation, frequency of breathing, tidal volume, oxygen consumption (Vo(2)), carbondioxide production (Vco(2)), and respiratory exchange ratio (R) were monitored before and during exercise tests. No significant differences between groups were observed; furthermore, there were no differences in circulating somatomedin-C (SM-C) and free fatty acids (FFA) levels between groups. Blood glucose levels were similar before exercise and followed a similar pattern during tests in diabetic smokers and nonsmokers. Basal GH, cortisol, and AVP levels were similar in diabetic smokers, diabetic nonsmokers, normal smokers, and normal nonsmokers. In all groups, exercise induced a significant increase in the serum concentrations of all examined hormones. Increments were significantly higher in diabetic than in nondiabetic groups. No significant differences were observed between diabetic smokers and nonsmokers for all examined hormones. AVP responses during tests were similar in normal smokers and nonsmokers. In contrast, exercise-induced GH and cortisol increments were significantly lower in normal smokers than in normal nonsmokers. These data support the hypothesis that in normal subjects habitual nicotine consumption may attenuate both GH and cortisol responses to a releasing stimulation, such as physical exercise. This phenomenon may represent an expression of adaptation of nicotinic neurotransmission to chronic stimulation. Furthermore, the data show that the effect induced by habitual smoking is absent in diabetics, probably because of diabetes-induced neuroendocrine alterations in the central nervous system.
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PMID:Difference between diabetic and nondiabetic smokers in the pituitary response to physical exercise. 1533 75

Maintenance of fluid homeostasis during periods of heightened physical stress can be best evaluated in humans using exercise as a model. Although it is well established that arginine vasopressin (AVP), aldosterone and atrial natriuretic peptide (ANP) are the principle hormones regulating fluid balance at rest, the potential contributions of other related endocrine factors, such as oxytocin (OT) and brain natriuretic peptide (BNP), have not been well described during exercise. Seven endurance-trained runners completed three separate running trials: a maximal test to exhaustion (high intensity), a 60-min treadmill run (steady state), and a 56 km ultramarathon (prolonged endurance exercise). Statistically significant pre- to post-run increases were found only following the ultramarathon in [AVP](p) (1.9 vs 6.7 pg/ml; P<0.05), [OT](p) (1.5 vs 3.5 pg/ml; P<0.05), [NT-proBNP](p) (23.6 vs 117.9 pg/ml; P<0.01), [interleukin 6](p) (4.0 vs 59.6 pg/ml; P<0.05), [cortisol](p) (14.6 vs 32.6 microg/ml; P<0.01), [corticosterone](p) (652.8 vs 3491.4 ng/ml; P<0.05) and [11-deoxycortisol](p) (0.1 vs 0.5 microg/ml; P<0.05) while a significant post-run increase in [aldosterone](p) was documented after high-intensity (4.9 vs 12.5 ng/ml; P<0.05), steady-state (6.1 vs 16.9 ng/ml; P<0.05) and prolonged endurance running (2.6 vs 19.7 ng/ml; P<0.05). Similarly, changes in fluid balance parameters were significantly different between the ultramarathon versus high-intensity and steady-state running with regard to plasma volume contraction (less % contraction), body weight loss (increased % weight loss), plasma [Na(+)] Delta (decreased from baseline), and urine osmolality Delta (increase from baseline). Hypothetically driven relationships between [OT](p) and [AVP](p) (r=0.69; P<0.01) and between [NT-proBNP](p) Delta and plasma [Na(+)] Delta (r=-0.79; P<0.001)--combined with the significant and unexpected pre- to post-race increases after prolonged endurance exercise--allows for possible speculation that OT and BNP may assist their better known companion hormones (AVP and ANP) in the regulation of fluid balance during conditions of extreme physical stress.
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PMID:Acute changes in endocrine and fluid balance markers during high-intensity, steady-state, and prolonged endurance running: unexpected increases in oxytocin and brain natriuretic peptide during exercise. 1879 10

The parallel response of sweat rate and urine production to changes in plasma osmolality and volume support a role for arginine vasopressin (AVP) as the main endocrine regulator of both excretions. A maximal test to exhaustion and a steady-state run on a motorised treadmill were both completed by 10 moderately trained runners, 1 week apart. Sweat, urine and serum sodium concentrations ([Na+]) were evaluated in association with the plasma concentrations of cytokines, neurohypophyseal and natriuretic peptides, and adrenal steroid hormones. When data from both the high-intensity and steady-state runs were combined, significant linear correlations were noted between: sweat [Na+] versus postexercise urine [Na+] (r=0.80; p<0.001), postexercise serum [Na+] versus both postexercise urine [Na+] (r=0.56; p<0.05) and sweat [Na+] (r=0.64; p<0.01) and postexercise urine [Na+] versus postexercise plasma arginine vasopressin concentration ([AVP](P)) (r=0.48; p<0.05). A significant positive correlation was noted between postexercise [AVP](P) and sweat [Na+] during the steady-state condition only (r=0.66; p<0.05). These correlations suggest that changes in serum [Na+] during exercise may evoke corresponding changes in sweat and urine [Na+], which are likely regulated coordinately by changes in [AVP](P) to preserve body fluid homeostasis.
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PMID:Acute changes in arginine vasopressin, sweat, urine and serum sodium concentrations in exercising humans: does a coordinated homeostatic relationship exist? 1880 73

A regulatory effect of arginine vasopressin (AVP) on sweat water conservation has been hypothesized but not definitively evaluated. AVP-mediated insertion of sweat and salivary gland aquaporin-5 (AQP5) water channels through activation of the vasopressin type 2 receptor (V2R) remains an attractive, yet unexplored, mechanism that could result in a more concentrated sweat with resultant decreased water loss. Ten runners participated in a double-blind randomized control treadmill trial under three separate pharmacological conditions: a placebo, V2R agonist (0.2 mg desmopressin), or V2R antagonist (30 mg tolvaptan). After a familiarization trial, runners ran for 60 min at 60% of peak speed followed by a performance trial to volitional exhaustion. Outcome variables were collected at three exercise time points: baseline, after the steady-state run, and after the performance run. Body weight losses were <2% across all three trials. Significant pharmacological condition effects were noted for urine osmolality [F = 84.98; P < 0.0001] and urine sodium concentration ([Na(+)]) [F = 38.9; P < 0.0001], which verified both pharmacological activation and inhibition of the V2R at the kidney collecting duct. Plasma osmolality and [Na(+)] demonstrated significant exercise (F = 26.0 and F = 11.1; P < 0.0001) and condition (F = 5.1 and F = 3.8; P < 0.05) effects (osmolality and [Na(+)], respectively). No significant exercise or condition effects were noted for either sweat or salivary [Na(+)]. Significant exercise effects were noted for plasma [AVP] (F = 22.3; P < 0.0001), peak core temperature (F = 103.3; P < 0.0001), percent body weight change (F = 6.3; P = 0.02), plasma volume change (F = 21.8; P < 0.0001), and thirst rating (F = 78.2; P < 0.0001). Performance time was not altered between conditions (P = 0.80). In summary, AVP acting at V2R does not appear to regulate water losses from body fluids other than renal excretion during exercise.
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PMID:Characterization of the effects of the vasopressin V2 receptor on sweating, fluid balance, and performance during exercise. 2494 42


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