Summary
The authors reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of cholesterol in rabbits. In such circumstances, platelet aggregability to ADP was examined by 2 methods: 1. measurement of intensity of platelet aggregation induced by ADP using the optical density method and 2. determination of minimum concentration of ADP solution to induce platelet aggregation using a light microscope. Three hours after oral administration of 1 g/kg of cholesterol, the intensity of aggregation in 12 rabbits increased to 106.0 ±2.4% (mean ± S. E.) by 10 ìM, 108.5 ±2.6% by 3 ìM and 110.2 ±3.7% of the value before the administration by 1 ìM of ADP. The differences were statistically significant (P <0.05). At that time, platelet in CPRP collected after cholesterol intake were aggregated by eight-times diluted ADP solution compared to that collected before cholesterol administration in 2 rabbits, four-times in 4 and two-times in 3 among 10 cases. Pyridinolcarbamate, which showed preventive effect against appearance of edematous changes in aortic wall induced by cholesterol and/or adrenaline, prevented these phenomena, when it was given 10 mg/kg orally 3 hours prior to cholesterol administration.
