Effects Of Androgens In The Onset And Magnitude Of Salt – Induced Hypertension In Male Sprague – Dawley Rats

ABSTRACT

Blood pressure is consistently higher in males compared with females from puberty onwards and men show an increased risk for hypertension compared to women. The gender disparity in cardiovascular functions and diseases has been linked to the effect of sex hormones on vascular reactivity. Although previous studies have suggested that the effect of chronic exposure to testosterone is an increase in vascular tone, it therefore implies that lack of testosterone should elicit vasorelaxation. Salt-sensitive hypertension in humans is associated with higher morbidity and mortality which may also be gender related. The role of gender in salt-sensitivity is not clear and the long-term effects of androgens on vascular reactivity especially in salt-induced hypertension have not been studied experimentally. Therefore experiments were designed to assess the effects of androgens on the development of salt-induced hypertension in male Sprague-Dawley rats by assessing vascular relaxation response to agonist as well as vascular smooth muscle histomorphology in orchidectomy-induced androgen deficient rats placed on a normal or high salt diet with or without testosterone supplementation. Weanling male Sprague-Dawley rats aged 8 weeks were divided into 8 groups of 16 rats each. They were either bilaterally orchidectomised or sham-operated under anaesthesia, with or without testosterone replacement (10mg/kg sustanon 250® i.m once in 3 weeks). They were placed on normal (0.3%) or high (8%) NaCl diet for 6 weeks. Arterial blood pressure was determined in conscious rats before and weekly throughout the experimental period using noninvasive tail cuff method. Terminal arterial blood pressure was also determined via femoral artery cannulation.