title: Estrogen influences stimulated water intake by ovariectomized female rats.
abstract: To further elucidate the influence of estrogen on water consumption, we examined water intake by adult female rats stimulated by water deprivation, injection of hypertonic saline or injection of isoproterenol (ISOP), a beta-adrenergic agonist that activates the renin-angiotensin system (RAS). Rats were ovariectomized (OVX) then injected with estradiol benzoate (EB; 10 microg/0.1 ml oil) or the oil vehicle (OIL; 0.1 ml) for 2 consecutive days. Twenty-four hours after the second injection, rats were deprived of food and water. On the following day, rats were given water and intake was measured after 2 h. EB significantly decreased water intake compared with that by OIL-treated rats following water deprivation. Two additional groups of adult female rats were OVX and treated with EB or OIL. Forty-eight hours after EB or OIL treatment, rats were injected with hypertonic saline (1 ml of 2 M NaCl) or ISOP (30 microg/kg in 0.15 M saline) and water intake was measured after 2 h. EB significantly attenuated water intake following ISOP but not after hypertonic saline. Finally, we examined plasma sodium concentration (pNa) after hypertonic saline and plasma renin activity (PRA) after ISOP in EB- and OIL-treated rats and found no differences in pNa or PRA. These results suggest that the stimuli for water intake after hypertonic saline and ISOP were comparable in EB- and OIL-treated rats. Taken together, these results raise the possibility that EB attenuation of stimulated water intake is specific to water intake elicited by activation of the RAS.
authors.affiliation: Department of Psychology, Florida State University, Tallahassee, FL 32306-1270, USA.
authors.forename: Eric G
authors.initials: EG
authors.lastname: Krause
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Curtis
authors.forename: Linda M
authors.initials: LM
authors.lastname: Davis
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Stowe
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Contreras
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004326:Drinking / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007279:Injections, Subcutaneous; D007545:Isoproterenol / Q000494:pharmacology; D009994:Osmolar Concentration; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000097:blood; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage; D012964:Sodium / Q000097:blood; D014868:Water Deprivation
chemical_list: D000318:Adrenergic beta-Agonists; D012462:Saline Solution, Hypertonic; D004958:Estradiol; D012964:Sodium; D012083:Renin; D007545:Isoproterenol