Gender dimorphism in renal kallikrein kinin system. Mineralocorticoid and sexual hormone modulation

NATALIA CORBERA, PABLO AZURMENDI, FERNANDO IBARRA, RODOLFO MARTÍN, ELISABET ODDO, ELVIRA ARRIZURIETA.

Rio de Janeiro

Congreso; World Congress of Nephrology; 2007

Sociedad Internacional de Nefrología

Gender dimorphism in renal kallikrein kinin system. Mineralocorticoid and sexual hormone modulation. Natalia Corbera, Pablo Azurmendi, Fernando Ibarra, Rodolfo Martín, Elisabet Oddo, Elvira Arrizurieta. Inst Invest Méd Alfredo Lanari, Fac Med, University of Buenos Aires, Buenos Aires, Argentina. <Ilanari@pinos.com>   Prepuberal gonadectomy (Gx) exerts both, a blood pressure lowering effect and an aldosterone dependent urinary kallikrein activity (UK) increase in SHR (Clin Exp Hypertension 28, 2, 2006). To further explore the mechanism involved in this UK  increase, UK,  renal cortical kallikrein activity (RK) and renal cortical  kallikrein mRNA were measured in SHR (n=20) of either sex at twelve weeks of age. Half of the animals were gonadectomized after weaning. At the time of the study, a 24hs urine collection was made for UK determination and, thereafter, the kidneys were surgically excised. Renal cortical tissue was separated to measure RK and kallikrein mRNA content. UK and RK were assayed by the amydolitic method using a synthetic substrate (S2266) and kallikrein mRNA by RT-PCR. Anova, followed by post hoc tests were used for statistic analysis.  UK (nkat/d/100g bwt) was higher in female than in male SHR,  44.8 ± 2.33 and 29.4 ± 1.92 (p<0.05) and increased after Gx to 91.4 ± 5.73 and 89.4 ± 4.86 , respectively (p<0.001 in both cases). RK (nkat/g), instead, was lower in intact female than male SHR, 8.6 ± 0.02 vs 21.8 ± 2.07 (p<0.05). After Gx, RK levels were not different between male and female rats. Kallikrein mRNA (expressed as the kallikrein / ß- actin ratio) was higher in intact female than in male SHR (0.824 ± 0.012 vs 0.598 ± 0.027, p<0.01) and, no significant changes were observed in kidney cortex mRNA in either sex, after Gx. UK, RK and Kallikrein mRNA was different between intact female and male SHR, indicating a sexual dimorphism for kallilkrein kinin system. This gender difference disappeared after gonads removal. Taken together, these data suggests that, besides the already known aldosterone influence, sexual hormones participate in the renal kallikrein kinin system modulation.