Oestradiol effects on neuroendocrine responses induced by water deprivation in rats.
Water deprivation (WD) induces changes in plasma volume and osmolality, which in turn activate several responses, including thirst, the activation of the renin-angiotensin system (RAS) and vasopressin (AVP) and oxytocin (OT) secretion. These systems seem to be influenced by oestradiol, as evidenced by the expression of its receptor in brain areas that control fluid balance. Thus, we investigated the effects of oestradiol treatment on behavioural and neuroendocrine changes of ovariectomized rats in response to WD. We observed that in response to WD, oestradiol treatment attenuated water intake, plasma osmolality and haematocrit but did not change urinary volume or osmolality. Moreover, oestradiol potentiated WD-induced AVP secretion, but did not alter the plasma OT or angiotensin II (Ang II) concentrations. Immunohistochemical data showed that oestradiol potentiated vasopressinergic neuronal activation in the lateral magnocellular PVN (PaLM) and supraoptic (SON) nuclei but did not induce further changes in Fos expression in the median preoptic nucleus (MnPO) or subfornical organ (SFO) or in oxytocinergic neuronal activation in the SON and PVN of WD rats. Regarding mRNA expression, oestradiol increased OT mRNA expression in the SON and PVN under basal conditions and after WD, but did not induce additional changes in the mRNA expression for AVP in the SON or PVN. It also did not affect the mRNA expression of RAS components in the PVN. In conclusion, our results show that oestradiol acts mainly on the vasopressinergic system in response to WD, potentiating vasopressinergic neuronal activation and AVP secretion without altering AVP mRNA expression.
Department of PhysiologyFaculty of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil tativilhenafranco@gmail.com.
Tatiane
T
Vilhena-Franco
Department of Physiological SciencesInstitute of Biological and Healthy Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil.|Department of PhysiologyFaculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
André Souza
AS
Mecawi
Department of PhysiologyFaculty of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil.
Lucila Leico Kagohara
LL
Elias
Department of PhysiologyFaculty of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil.
José
J
Antunes-Rodrigues
D000818:Animals; D001127:Arginine Vasopressin / Q000819:agonists / Q000032:analysis / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects; D003681:Dehydration / Q000503:physiopathology* / Q000628:therapy; D004326:Drinking / Q000187:drug effects; D004958:Estradiol / Q000627:therapeutic use*; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000627:therapeutic use*; D005260:Female; D005440:Fluid Therapy; D005786:Gene Expression Regulation / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010052:Ovariectomy / Q000009:adverse effects; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D011301:Preoptic Area / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D017208:Rats, Wistar; D013356:Subfornical Organ / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D013495:Supraoptic Nucleus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D003689:Vestibular Nucleus, Lateral / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D014883:Water-Electrolyte Imbalance / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*
D004967:Estrogens; D009419:Nerve Tissue Proteins; D001127:Arginine Vasopressin; D004958:Estradiol
angiotensin; oestradiol; oxytocin; vasopressin; water deprivation