Gender differences in blood pressure, renal function and response to a high-sodium diet in Wistar rats

Abstract

Introduction: It is known that sex is a determinant of renal sodium regulation and blood pressure. Methods: Male and female Wistar rats, which were 150 days old and a diet with normal or high levels of sodium (NaCl 1% v.o.), were studied for the last five days. Mean blood pressure (MBP), natriuresis, glomerular filtration rate (GFR), renal plasma flow (RPF) and plasma aldosterone level were established. The following were studied: expressions of total Na+,K+,-ATPase (t-NKA); dephosphorylated NKA (d-NKA); cytochrome P4504A (CYP4A); Na+K+-2Cl- (NKCC2) and Na+/Cl- (NCC) cotransporters. The mRNA expression of the NKA α1 (Atp1a1) chain was examined through PCR analysis in the renal cortex and marrow. Results: Male rats having both types of diet showed higher MBP and lower natriuresis. High sodium intake triggered lower aldosterone levels in both sexes; GFR was lower in females and RPF was higher in males (4.09 ± 0.17 vs. 2.81 ± 0.12 ml/min/gr; p<0.01 vs. diet with a normal sodium level). Marrow t-NKA, d-NKA and Atp1a1 were higher in males on both diets. High sodium intake caused lower marrow t-NKA as well as lower cortex and marrow d-NKA in females. In the case of males, only marrow d-NKA decreased. Furthermore, females showed a higher level of CYP4A and lower levels of NKCC2 and NCC, whereas males showed higher levels of NKCC2 and no variations in NCC. Conclusion: Sex conditions blood pressure and sodium balance, reducing resorption in females and increasing RPF in males. This suggests the possibility of studying sodium metabolism disorders differently according to sex.

Keywords

• sexo
• diferencias de género
• balance de sodio
• presión arterial
• transportadores de sodio
• sodio
• ratas Wistar
• enfermedades metabólicas