SEX CHROMOSOME COMPLEMENT INVOLVEMENT IN VASOPRESSIN GENE EXPRESSION INDUCED BY WATER DEPRIVATION

DADAM, FLORENCIA; MECAWI, ANDRÉ; CAMBIASSO, M.JULIA; ANTUNES-RODRIGUES, JOSÉ; VIVAS, LAURA ; CAEIRO, XIMENA E

Chicago

Congreso; Experimental Biology; 2017

Sex chromosome complement involvement in vasopressin gene expression induced by water deprivationDadam, Florencia1, Mecawi, André2, Cambiasso, M.Julia1, Antunes-Rodrigues, José2, Vivas, Laura1, Caeiro,XimenaE1.1-Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET-Universidad Nacional Córdoba. Córdoba,Argentina. 2-Departamento de Fisiologia, Faculdade de Medicina de Ribeirao Preto, Universidade de Sao Paulo,Ribeirao Preto,SP, BrasilVasopressin (AVP) is involved in the control of blood pressure and water balance. Basic and clinical data suggest thereare sex differences in the expression and function of AVP that cannot be entirely explained solely as a result of gonadalsteroid action. This study aimed to define whether sex chromosome complement (SCC) may differentially modulate sexdifferencesin the vasopressin gene expressionin response to osmotic stimulation.In order to evaluate whether SCC may differentially modulate vasopressin gene expression we used mice of the "fourcore genotypes" model, in which the effect of gonadal sex and SCC are dissociated, allowing comparisons of sexuallydimorphic traits between XX and XY females as well as in XX and XYmales. Comparing these genotypes, it is possibleto segregate the role of a) SCC (comparing mice with the same gonadal type but different SCC: XX vs. XY) b) sex(femalesvs. male) and c) the interaction of SCC and sex.To remove the activational effects of sex hormones, that might mask the modulatory action of SCC and theorganizational hormonal effects, mice were gonadectomized and 15 days later were submitted to a water deprivationprotocol (DEP group). Control groups remained with access to water and normal diet (CON group). Twenty four hourslater, brains and plasma of all groups were collected to assess plasma electrolytes and osmolality and to evaluaterelative gene expression ofAVP at the supraoptic (SON) and paraventricular nuclei (PVN).The statistical analysis showed a significant effect of treatment for both, osmolality and plasma Cl- levels {F(1,40)=4,91p <0,05; F(1,39)=4,03 p <0,05 respectively, n=6/group.}, however no sex nor SCC effects were observed. On thecontrary, a significant effect of the interaction of treatment and SCC factors was observed in the AVP genetic expressionat SON {F(1,13)=5,91 p<0,05} n=3-4/group}. Regardless of sex (male or female) XY-DEP mice (XY-male and XYfemale)expressed higher AVP mRNA levels compared to XY-CON animals. However, XX mice (both XX-male and XXfemale)showed similar levels of AVP mRNA expression for both controls and deprived groups (XX-CON and XX-DEP).At the PVN no statistical significant differences were observed. These results reveal a modulatory effect of sexchromosome complement on water deprived AVP gene expression within the SON, whatmay underlie sex differences inthe regulationofvasopressin secretion.Supportedby:ANPCyT, ISN,SECyT,Mincyt-Cba,CnPq,CONICET.