Influence of estrogen and 5‐HT1A receptors in electrolyte balance and endocrine in ovariectomized rats

Abstract

Thus, we examined in the present study the endocrine response in ovariectomized (OVX) rats submitted to oil or estrogen treatment (OVX‐E2 group estradiol cypionate, 100microg/kg, SC, during 14 days) and to treatment with the 8‐OH‐DPAT(8‐hydroxy‐di‐propilamino tetraline, 5‐HT1A receptor agonist, 250microg/kg, IP for 7 days) or vehicle (0.9% NaCl) during 7 days). We also investigated a possible correlation between serotonergic functional status and E2 replacement on the plasma levels of angiotensin I and II (ANG I, II), oxytocin (OT), natriuretic peptide (ANP) and corticosterone (CORT) in basal condition and after sodium depletion. The ANG I and ANG II release and respective mechanisms seem to be depending of the condition of the animal or 8‐OH‐DPAT treatment. Chronic 8‐OH‐DPAT in basal condition increased the ANG I plasma concentration while the E2 seems to attenuate this response following sodium depletion. The OT and CORT plasma levels at basal condition were enhanced by association of the two treatments. E2 replacement, both at baseline and depletion conditions, increased OT and CORT plasma levels. Additionally we did not observe estrogen influence on plasma CORT concentrations following sodium depletion; on the other hand, the 8‐OH‐DPAT seems to be critical to enhance the ANP secretion following sodium depletion. The serotonergic system seems to recruit different endocrine mechanisms regarding the homeostatic condition of the animal.