AJP - Regulatory, Integrative and Comparative Physiology, Vol 272, Issue 4 1084-R1087, Copyright © 1997 by American Physiological Society

ARTICLES

Effect of exposure to hypoxia from birth on aldosterone in rabbits: role of unesterified fatty acids

H. Raff, B. M. Jankowski, T. L. Goodfriend, J. E. Baker and P. E. Papanek
Department of Medicine, Medical College of Wisconsin, Milwaukee 53226, USA.

Hypoxia and fluid and electrolyte disturbances are serious risks to normal postnatal development. Because a decrease in inspired O2 (hypoxic hypoxia) inhibits aldosterone synthesis in the adult and aldosterone controls water and electrolyte balance, we studied adrenocortical function in rabbits exposed to normobaric normoxia or hypoxic hypoxia (fraction of inspired O2 0.09) from birth. At 21 days of age, rabbits were anesthetized, the adrenals were rapidly removed, and the adrenal capsules containing mostly zona glomerulosa cells were separated. Cells were dispersed with collagenase and studied in vitro. Hypoxia in vivo resulted in a 73% decrease in basal aldosterone release and a 86% decrease in adenosine 3',5'-cyclic monophosphate-stimulated aldosterone release in vitro. We hypothesized that increased unesterified fatty acids could be partly responsible for inhibition of aldosterone synthesis. Total serum unesterified fatty acids in hypoxic kits were significantly increased (298 +/- 14 micromol/l) compared with normoxic kits (184 +/- 31 micromol/l). When cells from hypoxic rabbits were washed with fatty acid-free albumin and studied under conditions devoid of fatty acids, aldosterone production was partially restored. Corticosterone production was not affected by washing. Washing had no effect on aldosterone synthesis by cells from normoxic rats. Finally, exposing washed zona glomerulosa cells to oleic acid (10-50 microM) inhibited aldosteronogenesis. We conclude that exposure to hypoxia from birth attenuates aldosterone production in part due to an increase in levels of unesterified fatty acid levels.

This article has been cited by other articles:

				E. D. Bruder, J. K. Taylor, K. J. Kamer, and H. Raff Development of the ACTH and corticosterone response to acute hypoxia in the neonatal rat Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2008; 295(4): R1195 - R1203. [Abstract] [Full Text] [PDF]

				H. Raff, E. D. Bruder, B. M. Jankowski, and T. L. Goodfriend Neonatal hypoxic hyperlipidemia in the rat: effects on aldosterone and corticosterone synthesis in vitro Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2000; 278(3): R663 - R668. [Abstract] [Full Text] [PDF]