Aortic collagen synthesis in rabbits following removal of atherogenic diet.

Male adult rabbits were divided into five experimental groups and were fed a 2% cholesterol diet using the following schedule: (A) two groups, normal control diet; (B) one group, 60 days continuous diet (60 day); (C) one group, 30 days cholesterol 30 days control diet (3030); (D) one group, 60 days cholesterol, 30 days control diet (60-30). Aortic collagen synthesis was estimated by measuring tissue prolyl hydroxylase activity and tissue cholesterol was measured following thin layer chromatography. In the 30-30 and 60-30 animals, the removal of cholesterol from the diet caused a rapid fall in serum cholesterol values which slowed the rate of aortic cholesterol accumulation. Collagen synthetic activity was significantly elevated in the 60-30 rabbits but was at control levels of both the 60 day and 3030 rabbits. The results demonstrate that the onset of increased aortic collagen synthesis is accompanied by an increase in the rate of cholesterol accumulation.