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Record Details

Record 53 of 15052
Increased renal tubular sodium reabsorption during exercise-induced hypervolemia in humans
Author and Affiliation:
Nagashima, K.(The John B. Pierce Laboratory, New Haven, Connecticut 06519, United States)
Wu, J.
Kavouras, S. A.
Mack, G. W.
Abstract: We tested the hypothesis that renal tubular Na(+) reabsorption increased during the first 24 h of exercise-induced plasma volume expansion. Renal function was assessed 1 day after no-exercise control (C) or intermittent cycle ergometer exercise (Ex, 85% of peak O(2) uptake) for 2 h before and 3 h after saline loading (12.5 ml/kg over 30 min) in seven subjects. Ex reduced renal blood flow (p-aminohippurate clearance) compared with C (0.83 +/- 0.12 vs. 1.49 +/- 0.24 l/min, P < 0.05) but did not influence glomerular filtration rates (97 +/- 10 ml/min, inulin clearance). Fractional tubular reabsorption of Na(+) in the proximal tubules was higher in Ex than in C (P < 0.05). Saline loading decreased fractional tubular reabsorption of Na(+) from 99.1 +/- 0.1 to 98.7 +/- 0.1% (P < 0.05) in C but not in Ex (99.3 +/- 0.1 to 99.4 +/- 0.1%). Saline loading reduced plasma renin activity and plasma arginine vasopressin levels in C and Ex, although the magnitude of decrease was greater in C (P < 0.05). These results indicate that, during the acute phase of exercise-induced plasma volume expansion, increased tubular Na(+) reabsorption is directed primarily to the proximal tubules and is associated with a decrease in renal blood flow. In addition, saline infusion caused a smaller reduction in fluid-regulating hormones in Ex. The attenuated volume-regulatory response acts to preserve distal tubular Na(+) reabsorption during saline infusion 24 h after exercise.
Publication Date: Sep 01, 2001
Document ID:
20040112321
(Acquired Oct 05, 2004)
Subject Category: AEROSPACE MEDICINE
Document Type: Journal Article
Publication Information: Journal of applied physiology (Bethesda, Md. : 1985) (ISSN 8750-7587); Volume 91; 3; 1229-36
Publisher Information: United States
Contract/Grant/Task Num: HL-20634
Description: In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: BLOOD VOLUME; HYPERVOLEMIA; KIDNEYS; PHYSICAL EXERCISE; SODIUM; ADULTS; BLOOD CIRCULATION; FEMALES; LITHIUM; MALES; OSMOSIS; RENAL FUNCTION; URINE
Other Descriptors: BLOOD VOLUME/PHYSIOLOGY; EXERCISE/PHYSIOLOGY; KIDNEY TUBULES, DISTAL/METABOLISM; KIDNEY TUBULES, PROXIMAL/METABOLISM; SODIUM/METABOLISM; ADULT; FEMALE; GLOMERULAR FILTRATION RATE; HUMAN; LITHIUM/PHARMACOKINETICS; MALE; OSMOTIC PRESSURE; RENAL CIRCULATION/PHYSIOLOGY; SUPPORT, U.S. GOV'T, NON-P.H.S; SUPPORT, U.S. GOV'T, P.H.S; URINE; NASA DISCIPLINE CARDIOPULMONARY; NON-NASA CENTER
Availability Source: Other Sources
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