Adrenalectomy decreases nacl intake of rats fed low-calcium
diets.
Tordoff, Michael G.
Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA
19104-3308
APStracts 2:0190R, 1995.
Five studies were conducted to characterize the effects on NaCl intake
of the interaction between adrenalectomy (ADX) and dietary calcium.
Intact rats fed low-calcium diets (0 or 25 mmol Ca2+/kg diet)
approximately quadrupled intake of 300 or 500 mM NaCl solution
relative to intact rats fed diets with moderate or high calcium
content (125, 150, or 500 mmol Ca2+/kg diet). Adrenalectomy
approximately doubled NaCl intake of rats fed moderate or high
-calcium diets but decreased NaCl intake of rats fed low-calcium diets
to levels similar to those of ADX rats fed moderate or high-calcium
diets. Aldosterone replacement (2.4 [mu]g/day, s.c.) reduced NaCl
intake of ADX rats fed control diets to below levels of intact
controls, but the same treatment to ADX rats fed low-calcium diet had
no effect on NaCl intake. The reduction in NaCl intake produced by
ADX in rats fed low-calcium diet could not be attributed to general
debilitation, damage to the adrenal medulla, or altered metabolism of
sodium or calcium (i.e., plasma concentration, bone content or
balance). It is proposed that an adrenocortical hormone other than
aldosterone mediates the high salt intake of the calcium-deprived
rat, and thus the adrenal has both inhibitory and excitatory actions
on NaCl intake.
Received 31 March 1995; accepted in final form 30 June 1995.
APS Manuscript Number R213-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 18 July 1995.