Metabolic response after isoproterenol-induced myocardial infarction in arteriosclerotic breeder vs nonarteriosclerotic virgin intact and gonadectomized male rats.

Male, nonarteriosclerotic (virgin) intact and castrated, Sprague-Dawley rats and male, arteriosclerotic (breeder) rats were subjected to an acute and massive myocardial infarct, by treating them with two large, subcutaneous doses of isoproterenol, spaced 24 hr apart. Serum insulin and glucose rose abruptly after the first injection of isoproterenol, but not after the second injection. Free fatty acids rose, most markedly, in the intact, nonarteriosclerotic rats, less in the arteriosclerotic breeders, and least in the castrates. These changes in free fatty acids coincided with numerical survival, i.e., greatest number of survivors in castrates. The castrated males also manifested the least amount of congestive heart failure and showed the greatest capacity to affect myocardial repair. It is suggested that reduced androgen levels may have an ameliorative effect on the usual pathogenesis of isoproterenol-induced myocardial infarction in rats.