Sex differences in angiotensinII-stimulated fluid intake.

Abstract

What is the topic of this review? This report describes sex differences in the responses to angiotensinII, with a focus on fluid intake. What advances does it highlight? There are conflicting reports on the direction of the sex difference in fluid intake in response to angiotensinII. This review highlights how accounting for differences in body weight contributes to the discrepancies in the literature. In certain conditions, body weight influences fluid intake in a sex-specific manner. This review also highlights the divergent effects of oestrogen receptor activation on fluid intake, which are likely to underlie the discussed sex differences. Sex has a clear effect on the renin-angiotensin-aldosterone system. Although sex differences in the pressor response to angiotensinII (AngII) are well established, understanding of the sex differences in the fluid intake response to AngII is clouded by conflicting reports. Here, I suggest that accounting for differences in body weight contributes to the discrepancies in the literature. Our recent findings demonstrate that body weight influences AngII-stimulated water intake in certain conditions in male, but not in female rats. When differences in body weight are corrected for in the appropriate circumstances, we found that males consume more water in response to AngII compared with females. Males and females also show differences in drinking microstructure, i.e. bottle spout lick patterns, which provide clues into the mechanism(s) underlying this sex difference. Oestrogens, which inhibit AngII-stimulated fluid intake and circulate at higher concentrations in females, are likely to contribute to this sex difference. This review also discusses the diversity in oestrogen signalling via multiple oestrogen receptor subtypes, which selectively inhibit AngII-stimulated fluid intake.