METHODS: Ovariectomized female normotensive Wistar Kyoto (WKY) and Spontaneous hypertensive (SHR) rats were given six weeks treatment with testosterone via subcutaneous silastic implant. The rats were anesthetized and mean arterial pressure (MAP) was measured via direct cannulation of the carotid artery. Animals were sacrificed and kidneys were removed and subjected for α, β and γ-ENaC protein and mRNA expression analyses by Western blotting and Real-time polymerase chain reaction (qPCR), respectively. Distributions of α, β and γ-ENaC proteins in kidneys were observed by immunofluorescence. Plasma testosterone, aldosterone, electrolytes, osmolality, urea and creatinine levels were determined by biochemical assays. Analysis were also performed in non-testosterone treated orchidectomized and sham-operated male WKY and SHR rats.
RESULTS: Treatment of ovariectomized female WKY and SHR rats with testosterone causes increased in MAP but decreased in plasma aldosterone, sodium (Na+), osmolality and expression and distribution of α, β and γ-ENaC subunits in the kidneys. Orchidectomy decreased the MAP but increased plasma aldosterone, Na+, osmolality and α, β and γ-ENaC expression and distribution in the kidneys of male WKY and SHR rats.
CONCLUSIONS: Decreased in plasma aldosterone, Na+ and ENaC levels in kidneys under testosterone influence indicated that testosterone-induced increased in MAP were not due to increased plasma aldosterone and ENaC levels in kidneys, and thus the testosterone effect on MAP likely involve other mechanisms.
METHODS: In this cross-sectional study, 482 adults (223 men, 259 women) aged ≥18 years old were measured for body mass index (BMI), waist circumference (WC), waist-height ratio (WHtR), waist-hip ratio (WHR), and blood pressure. Receiver operating characteristic (ROC) analysis was used to determine the predictive ability of obesity indices for hypertension in men and women. Gender-specific logistic regression analyses were done to examine the association between obesity, defined by BMI, WC, WHtR and WHR, and hypertension.
RESULTS: Prevalence of hypertension was 25.5%. Overall, WHtR was the best predictor of the presence of hypertension, in both men and women. The optimal WHtR cut-off values for hypertension were 0.45 and 0.52 in men and women, respectively. Obese adults with WHtR ≥0.5 had about two times increased odds of having hypertension compared to non-obese adults.
CONCLUSIONS: WHtR may serve as a simple and inexpensive screening tool to identify individuals with hypertension in this relatively difficult to reach population.