Blood pressure independent sexual dimorphism in proteinuric response to high salt intake in Sprague‐Dawley rats.

Abstract

We examined if changes in blood pressure and proteinuria during chronic salt intake exhibit sex disparities in age‐matched male (♂; N=10) and female (♀; N=10) Sprague‐Dawley (SD) rats subjected to either normal (0.7% NaCl) or high salt (8% NaCl) diets for 2‐weeks. Metabolic studies, systolic blood pressures (SBP) measured by tail‐cuff method and proteinuria in 24‐h urine samples, were performed. Baseline SBP was not different between genders (♂:119.1±3 vs. ♀:119.0±4 mmHg) or after 2‐weeks on HS diet (♂:129.0±5 vs. ♀:125.6±6 mmHg). HS intake induced proteinuria in both sexes; however it was greater in male than in female rats [Day ‐1(♂:5±1 vs. ♀:3±1); Day 9 (♂:36±3 vs. ♀:17±2 mg/day); p<0.01]. By day 13, body weights were higher in ♂ than ♀ rats; however there was no difference with salt load [(male NS: 330±8 versus male HS: 324±7 g); ♀ NS: 217±12 vs. ♀ HS: 226±4 g)]. There were no sex dependent differences in food intake after it factored by body weight (♂ NS: 11±1 g/kg BW; ♂ HS: 12±1 g/kg BW; female NS: 11±2 g/kg BW; female HS: 13±1 g/kg BW; p=no significant). SBP under HS intake did not exhibit sexual dimorphism; however the augmented proteinuria in male rats may reflect a greater predisposition to develop renal injury with high salt consumption than female rats.Grants from the APS (2009 Frontiers in Physiology Research Host Awardees Program); NIH (P20‐RR‐017659; Tulane‐BIRCWH K12HD043451 award).