Estrogen inhibit salt‐overload induced hypernatremia in ovariectomized female rats (683.5)

Abstract

Since estrogen is controversially implicated on sodium balance, our aim in the present study was to evaluate the estrogen modulations on female rats under basal and salt‐overload conditions. Female Wistar rats were bilaterally ovariectomized (OVX) and randomly divided in two groups to receive estradiol benzoate (EB‐OVX, 10 µg/0.1 mL/animal, s.c.) or vehicle (OVX, 0.1 mL/animal, s.c.). The animals were placed in metabolic cages for adaptation; 7 days after the estradiol or vehicle treatement beggining, two experimental protocols were performed in OVX and EB‐OVX rats: i) basal water or water plus saline (0.075, 0.15 and 0.3 M NaCl) offering and, ii) salt‐overload (0.3 M NaCl offered as only fluids) during 3 or 15 days. OVX and EB‐OVX rats exhibited a decreased 0.3 M saline preference compared to hypotonic and isotonic solutions. Also, salt overloaded rats showed a progressive increase of hypertonic intake, as only fluid offered, with no changes induced by estrogen. However, estrogen induced a inhibition of hypernatremia on EB‐OVX rats induced by high salt ingestion when compared to OVX. Additionally, AVP and OT increasing in response to salt loading was not modulated by estrogen, meanwhile estrogen inhibited and attenuated the decrease on ANP and ANG II plasma concentrations, respectively. Taken together, our present findings suggest that estrogen participates on the control of natremia in salt‐overloaded rats.Grant Funding Source: Supported by FAPERJ and FAPESP