Elevated dietary sodium and testosterone treatment increases blood pressure and vessel responsiveness differentially in adult WKY and SHR female rats

Abstract

Dietary sodium (Na) and testosterone (T) can increase blood pressure (BP) and alter vessel responsiveness in both males and females. However, females typically gain some cardiovascular benefit from estrogen until menopause. The purpose of this study was to examine the role of dietary Na and T treatment on BP and resistance sized artery response to intraluminal pressure increases (Myo) in adult WKY and SHR female rats. Therefore, the hypothesis was that increased dietary Na along with T would increase BP and vessel responsiveness to a greater extent in T treated females. Gonadally intact adult (15 weeks old) SHR and WKY females were fed either normal Na (NNa, 0.3%) or high Na (HNa, 3%) diets and placed in either the control group or given T (n=5–10/group). Systolic blood pressure was measured via tail sphygmomanometry and arterial responsiveness was analyzed on isolated secondary mesenteric arteries using a pressure arteriograph system. Blood pressure was significantly higher in the HNa SHRs when compared to the WKY HNa females, (p<0.05), with T only minimally increasing BP. However, T significantly increased BP in the NNa SHR and WKY females (p<0.01). For both diets, SHR T females showed increased Myo (T and diet interaction F=4.3, p<0.05), with T having a minimal effect on Myo in WKY females. In conclusion, T along with the dietary effects of Na increased BP and Myo to a greater extent in SHR females.