Sex chromosome complement (SCC) involvement in the sexually dimorphic vasopressinergic system? P69

GODINO, A;; CAEIRO, X; CAMBIASSO, MJ.; GONZALEZ, L; VIVAS, L;

Acapulco

Simposio; RegPep2018, 22nd International Symposium on Regulatory Peptides, Acapulco, Mexico,; 2018

.

SEX CHROMOSOME COMPLEMENT INVOLVEMENT IN THE SEXUALLY DIMORPHIC VASOPRESSINERGIC SYSTEM Lihue Gonzalez, Andrea Godino, María J. Cambiasso, Laura Vivas, Ximena Caeiro INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina.Numerous studies indicate differences between males and females in the regulation of blood pressure and hydroelectrolyte balance control. This study aimed to explore the role of the sex chromosomes (XX / XY) and / or the organizational hormonal effects of gonadal steroids in the vasopressinergic sexual dimorphic response, analyzing the effect of desmopressin administration, a vasopressin V2 receptor (V2R) agonist on urinary osmolarity and the blood pressure regulation in response to systemic vasopressin administration. To carry out the aforementioned experiments we used gonadectomized male (XX and XY) and female (XX and XY) mice of the "four core genotypes" model, in which the effect of gonadal sex and sex chromosome complement (SCC) is dissociated, allowing comparisons of sexually dimorphic traits among XX and XY females, as well as in XX and XY males. Forty two days post gonadectomy, mice were subcutaneously injected with vehicle solution and desmopressin (1 mg / kg) and after a four hour period (with no access to water or food) urine samples were obtained for subsequent determination of osmolarity (Vapro Osmometer). The statistical analysis of desmopressin infusion showed a significant effect of the interaction of the treatment and sex factors {F (1,35) = 5.0650, p = 0.03080}, since male mice showed irrespectively of the SCC (XX-male and XY-male mice) a significant increase in urinary osmolarity when compared to females (both XX-females and XY-females). Furthermore, in anesthetized gonadectomized transgenic mice we evaluated changes in blood pressure in response to a 30 minute vasopressin infusion (0,2 UI/ml, infusion volume 100µl). The blood pressure results reveal a SCC modulatory effect on vasopressinergic pressor response; regardless of sex (male or female) XX-SCC mice showed a greater increase in blood pressure when compared to XY-SCC mice (XY-male and XY-female). In sum this evidence may indicate that in absence of the activating hormonal effect it would be the organizational hormonal factor that would be defining the sexually dimorphic urinary osmotic phenotype while sex differences in the pressor response to vasopressin infusion may be driven by the sex chromosomal complement factor. Support: ANPCyT, CONICET and Roemmers Foundation.