Induction of diverse arterial and myocardial lesions by adrenal regeneration hypertension in Sprague-Dawley versus spontaneously hypertensive rats

Abstract

Nonarteriosclerotic, virgin, Sprague-Dawley (SD), and spontaneously hypertensive (SHR) rats and arterio sclerotic breeder SD and SHR rats were subjected to adrenal regeneration-induced hypertension (ARH) with and without extra salt. ARH caused a marked increase in the blood pressure of SD rats and a mild increase in SHR rats; extra salt caused exacerbation of hypertension in SD rats only. Heart and kidney weights were greatly increased commensurate with blood pressure. Increased adrenal weight concomitant with thymus gland involution was considerable in SD and less marked in SHR rats. Testes and ovaries were involuted. Creatine phosphokinase and lactic dehydrogenase levels were abnormally high; blood triglycerides, FFA, glucose, and corticosterone decreased, and total cholesterol, glucose, and corticosterone increased in SD but decreased in SHR rats. Blood urea nitrogen levels were much more abnormally elevated in SD than in SHR rats. ARH did not induce arterial disease in the virgin SD or SHR rats, but it did produce a spectrum of arterial disease in SH breeders, e.g. aortic sclerosis, polyarteritis nodosa-like lesions, intimal cartilaginous metaplasia, and hyalin fibrosis. Altered adrenocortical steroidogenesis may have conditioned the arterial wall of SHR rats to develop diverse morphological changes, and extra salt is much more detrimental to normotensive rats (SD) than to genetically hypertensive rats.