Comparative effects of prolactin, perphenazine and reserpine on non-arteriosclerotic (virgin) vs arteriosclerotic (breeder) rats.

Non-arteriosclerotic, virgin and arteriosclerotic breeder rats were subjected to chronic treatment with prolactin or prolactin-releasing drugs such as perphenazine and reserpine for 12 weeks. Males and females responded to the prolactin as evidenced by increased milk secretion, adrenal hyperplasia and thymus gland involution. Although the prolactin- and reserpine-treated animals gained weight and manifested pituitary gland basophilia, the perphenazine-treated animals showed considerable loss of body weight as well as involution of the pituitary gland, ovaries and testes, suggesting a condition of induced hypopituitarism. Chronic treatment with prolactin, both directly and indirectly, caused uniform increases in serum enzymes, e.g., CPK, SGOT, SGPT and LDH, lipids, e.g., triglycerides, free fatty acids and cholesterol, glucose and BUN. Corticosterone production was enhanced by prolactin, reduced by perphenazine and unaffected by reserpine. Prolactin did not induce any arterial disease in the arteriosclerosis-resistant, virgin rats but it did cause eracerbation of the usual severity of arteriosclerosis in the hilar renal arteries of the arteries sclerosis-prone, breeder rats as well as an increased incidence of "old" and "new" foci of myocardial necrosis, characteristically found in breeder rats. It is suggested that hypothalamic control of prolactin as well as ACTH release may play a role in the spontaneous arteriosclerosis which develops in repeatedly-bred, male and female rats.