Date of Award


Degree Type


Degree Name

Master of Science in Pharmacology and Toxicology


Pharmacology and Toxicology

First Advisor

Robert L. Rodgers


Diabetes decreases systolic arterial pressure in the spontaneously hypertensive rat (SHR). Two possible mechanisms, a decrease in vascular collagen biosynthesis and an altered vascular reactivity, were investigated. Collagen biosynthesis, as indicated by prolyl hydroxylase activity, was reduced in the aorta in the diabetic SHR to a greater extent than the diabetic Wistar-Kyoto rat (WKY). Prolyl hydroxylase activity was also reduced, but to a lesser extent, in the aorta of food restricted and hypothyroid SHR and WKY rats. Streptozotocin (STZ)-induced diabetes increased the sensitivity of the mesenteric artery of both strains to methoxamine only. The response of the mesenteric artery of the SHR was increased, though not significantly, to norepinephrine and methoxamine. Therefore, it appears that the depressor effect of STZ in the SHR is not associated with a reduction in vascular reactivity. The results suggest that a reduction in collagen synthesis may play a role in the depressor effect of STZ in the SHR. The reduction in collagen biosynthesis in STZ-induced diabetes may in part be due to the altered nutritional state and a reduction in thyroid hormones associated with diabetes.