Salt Loading Effects on ENaC and Blood Pressure in Aged 129Sv Mice

Abstract

Essential hypertension in the elderly population is a major public health problem because these patients usually do not respond well to antihypertensive drugs. More than half the cases of essential hypertension are thought to be associated with salt sensitivity from excessive dietary salt intake. We hypothesized that salt loading augments renal epithelial sodium channel expression and blood pressure in aged 129Sv mice. The renal epithelial sodium channel regulates total body salt balance and blood pressure, but mechanisms for its regulation by dietary salt intake in the aged kidney are not completely known. Twelve month old 129Sv mice were subject to salt loading for 4 weeks. Water intake, urine production, blood pressure, and electrolytes in the urine were measured before and after salt loading. Both the total and cleaved forms of ENaC subunits were assessed by Western blotting and densitometric analysis. ENaC alpha protein was augmented in the kidneys of salt‐loaded hypertensive 129Sv mice compared to non‐salt loaded mice. Water intake, urine output, and systolic blood pressure significantly increased in the 129Sv mice after salt‐loading. Salt loading resulted in an increase in urinary sodium levels and a decrease in urinary potassium levels. These findings may provide new links between salt‐sensitivity, ENaC expression, and blood pressure regulation in the aged kidney.Support or Funding InformationThis project was funded by the U.S. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases (Grant K01 DK099617; to A.A.A.) and the University of Florida College of Medicine.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.