Effects of prostaglandins on the gender difference in the renal and
cardiovascular responses to vasopressin in conscious rats.
Wang, Yi-Xin, Joan T. Crofton, and Leonard Share.
Department of Physiology and Biophysics, The University of
Tennessee, Memphis, TN 38163
APStracts 3:0268R, 1996.
The present study was carried out to investigate whether
prostaglandins (PGs) are involved in the mechanism that contribute to
the sex difference in the antidiuretic and pressor actions of
vasopressin. The experiments were performed in conscious male and
non-estrous female rats. In hydrated rats, the graded infusion of
vasopressin (10 - 1000 pg. min-1. kg body wt-1) resulted in a dose
-dependent antidiuresis: decreases in urine flow and free water
clearance and an increase in urine osmolality. These responses were
significantly greater in male than in non-estrous female rats. Pre
-treatment with a cyclooxygenase inhibitor, indomethacin (10 mg.kg
body wt-1, iv), significantly enhanced the antidiuretic response to
vasopressin in both sexes. However, the magnitude of this enhancement
was greater in female than in male rats. Thus, indomethacin abolished
the sex difference in the antidiuretic response to vasopressin. In a
separate experiment in rats without water hydration and urine
collection, infusion of pressor doses of vasopressin (1000 - 6000
pg.min-1 . kg body wt -1) resulted in a greater increase in blood
pressure in male than in non-estrous female rats. Treatment with
indomethacin enhanced this response equivalently in both sexes, and
thus, did not affect the sex difference in the pressor action of
vasopressin. These data indicate that renal PGs may mediate, at least
in part, the sex difference in the antidiuretic action of
vasopressin, while vascular PGs seem not to play an important role in
the sex difference in the pressor action of vasopressin.
Received 15 November 1995; accepted in final form 20 June 1996.
APS Manuscript Number R717-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996