Effects of Testosterone on Vascular Reactivity in Male Sprague – Dawley Rats Fed a High Salt Diet

Abstract

Sex hormone‐dependents vascular reactivity is an underlying factor contributing to gender differences in salt‐dependent hypertension. This study evaluated the role of androgens on vascular reactivity in the perfused hind limb preparation in salt ‐ induced hypertension. Weanling male rats (8 weeks old; weight, 180 – 200)g were bilaterally orchidectomised or sham‐operated with or without testosterone replacement (10mg/kg sustanon 250® i.m once in 3 weeks), and were placed on normal (0.3%) or high (4%) NaCl diet for 6 weeks. Rats fed a high salt diet (HSD) showed increases in arterial blood pressure (BP) [11.92%], renal vascular resistance (RVR) [17.24%], fluid balance (FB) [92%], that was accompanied by decreased plasma nitric oxide (NO) production [65.62%]. Orchidectomy reversed but testosterone replacement restored the increased (P < 0.05) BP, RVR, and FB observed in the rats fed a HSD. HSD increased response to PE [30.31%] but this was reversed and restored by orchidectomy and testosterone replacement respectively. HSD also impaired vasorelaxation to ACh [29.11%] and SNP [44.22%]. Orchidectomy attenuated the impaired relaxation response to ACh and SNP observed in the HSD fed rats. Testosterone promotes the impairment of vascular function observed in HSD and this may involve the NO pathway.