Sexual dimorphism in blood pressure regulation during ang ii infusion: involvement of sex chromosome complement and hormonal effects

DADAM FLORENCIA MARIA; XIMENA CAEIRO; LAURA VIVAS

Cordoba

Workshop; The neurohumoral control of body fluid and cardiovascular homeostasis in males and females - vive la difference!; 2019

Evidence demonstrate that the pressor response to Ang II infusion is sexually dimorphic under physiological and pathophysiological circumstances. But why do male and female show differences in rennin angiotensin system (RAS) activation and inhibition? Sex steroids can induce organizational (long-lasting or permanent) effect during critical periods of development but can also impart (temporary or reversible) activational effects. Furthermore, males and females also carry different sex chromosome complements (SCC:XY/XX) and thus are influenced throughout life by different genomes. Previous evidence demonstrates a modulatory effect of SCC in RAS receptor expression (brain and renal), as well as in the Ang II sexually dimorphic bradycardic barroreflex and hypertensive responses. In the present study we evaluated the involvement of SCC, organizational and activational hormone effect on changes in mean arterial pressure (MAP) in a 10 min Ang II infusion protocol. For this purpose, we used gonadectomized (Gdx) mice of the "four core genotype" model, in which the effect of gonadal sex and SCC is dissociated, allowing comparisons of sexually dimorphic traits between XX and XY females as well as in XX and XY males. For hormonal replacement experiments Gdx mice were daily injected with ß-estradiol or testosterone propionate (2ug/g) for a 4 day period.The statistical analysis reveal an interaction of SCC, organizational and activational hormonal effect during Ang II infusion {F(7,39=2,60 p