Comparative Studies on the Preventive Effect of Pyridinolcarbamate and Estrogen Against Aortic and Coronary Atherosclerosis of Cholesterol‐fed Rabbits

The antiatherosclerotic effects of pyridinolcarbamate and estrogen, both of which have a preventative effect against acute edematous vascular injury, were studied using 40 rabbits. Ten rabbits each received orally 0.1 mg/kg or 1 mg/kg of diethylstilbestrol, 10 mg/kg of pyridinolcarbamate or potato starch as a placebo. All were fed cholesterol for 15 weeks. Treatment with pyridinolcarbamate of 1 mg/kg of diethylstilbestrol was shown to exert a powerful effect in preventing the appearance of atheromatous changes (p<0.01) but 0.1 mg/kg of diethylstilbestrol did not show a preventative effect. The three treated groups exhibited protection against coronary atherosclerosis which was statistically significant when compared with the controls. Atheromas in rabbits treated with pyridinolcarbamate were characterized his‐tologically by the regeneration of smooth muscle fibers and those treated with diethylstilbestrol by fibrous healing. Necrotic foci or calcification was sometimes encountered, especially in the rabbits treated with 1 mg/kg of diethylstilbestrol. These preventative properties of the substances studied are possibly much related to inhibit permeability‐enhancing conditions of the arterial wall.