Endocrine and Metabolic Factors

Abstract

DR. GILLMAN: We had an interesting experience with rats whose arteries had been injured by feeding toxic doses of calciferol for five days. At this point 95% of animals had advanced arteriosclerosis with marked coronary stenosis. Nevertheless, there was a very remarkable pattern of dying between males and females some 300 days later when fed on a high fat diet. Both males and females were fed the high fat diet, but only the males all died, and they died at night within three weeks. I make the suggestion that the narrow vessel lumen might have become occluded at night when males were more likely to be feeding than the females, a thrombotic episode being precipitated by fat administration as well as by activity. We found that the plasma of males contained a higher concentration of fibrin before feeding the high fat diet than females (FIG. 1). Implantation of testosterone pellets into castrated male rats induced a marked increase in the plasma fibrin. Estradiol failed to completely depress this rise. Although fibrin concentration in gonadectomized males did not differ from that in normal males, after fat feeding there was a rise in fibrin. Fibrin levels of females approached the males when they were gonadectomized both basally and after fat.