AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 1 76-R83, Copyright © 1984 by American Physiological Society

ARTICLES

Sodium balance and aldosterone during dehydration and rehydration in the dog

T. N. Thrasher, C. E. Wade, L. C. Keil and D. J. Ramsay

The regulation of sodium metabolism and the renin-angiotensin-aldosterone system was evaluated during 24 h of water, but not food, deprivation and during rehydration in the dog. Dehydration caused increases in plasma concentrations of sodium (6.0 +/- 0.7 meq/l), protein (0.8 +/- 0.1 g/dl), vasopressin (5.3 +/- 0.9 pg/ml), and renin activity (3.5 +/- 1.1 ng AI X ml-1 X 3 h-1). Plasma aldosterone was unchanged and plasma potassium fell slightly (0.2 +/- 0.1 meq/l). During dehydration, food, and thus sodium intake fell by more than 10% in 12 of 19 dogs, but urinary sodium excretion increased significantly, leading to a negative sodium balance (1.9 +/- 0.2 meq/kg). Sodium retention was observed after rehydration and sodium balance; plasma electrolytes, vasopressin, and plasma renin activity (PRA) returned turned to control levels after the 1st day of recovery. However, plasma aldosterone was slightly elevated at this time, returning to control after the 2nd day of recovery. The dehydration-induced natriuresis could not be accounted for by a fall in plasma aldosterone. However, sodium retention following rehydration could be aldosterone dependent, because additional studies showed a threefold rise in plasma levels of the hormone 1 h after drinking. The acute rise in aldosterone correlated closely (r = 0.82) with the fall in plasma sodium after drinking but not with changes in adrenocorticotrophic hormone, PRA, or plasma potassium. It is concluded that natriuresis is a homeostatic response to dehydration as a means of ameliorating the rise in body fluid osmolality.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				C. Wotus and W. C. Engeland Differential regulation of adrenal corticosteroids after restriction-induced drinking in rats Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2003; 284(1): R183 - R191. [Abstract] [Full Text] [PDF]

				S. Chen, L. Cao, H. D. Intengan, M. Humphreys, and D. G. Gardner Osmoregulation of Endothelial Nitric-oxide Synthase Gene Expression in Inner Medullary Collecting Duct Cells. ROLE IN ACTIVATION OF THE TYPE A NATRIURETIC PEPTIDE RECEPTOR J. Biol. Chem., August 30, 2002; 277(36): 32498 - 32504. [Abstract] [Full Text] [PDF]

				K. E. Scrogin, D. F. McKeogh, and V. L. Brooks Is osmolality a long-term regulator of renal sympathetic nerve activity in conscious water-deprived rats? Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2002; 282(2): R560 - R568. [Abstract] [Full Text] [PDF]

				R. W. Kenefick, C. M. Maresh, L. E. Armstrong, J. W. Castellani, D. Riebe, M. E. Echegaray, and S. A. Kavorous Plasma vasopressin and aldosterone responses to oral and intravenous saline rehydration J Appl Physiol, December 1, 2000; 89(6): 2117 - 2122. [Abstract] [Full Text] [PDF]

				M. J. McKinley, M. D. Evered, and M. L. Mathai Renal Na excretion in dehydrated and rehydrated adrenalectomized sheep maintained with aldosterone Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2000; 279(1): R17 - R24. [Abstract] [Full Text] [PDF]

				L. J. Andersen, P. Norsk, L. B. Johansen, P. Christensen, T. Engstrom, and P. Bie Osmoregulatory control of renal sodium excretion after sodium loading in humans Am J Physiol Regulatory Integrative Comp Physiol, December 1, 1998; 275(6): R1833 - R1842. [Abstract] [Full Text] [PDF]