INCREASED CYCLIC-AMP IN AORTAS OF CHOLESTEROL-FED RABBITS

Cyclic Amp (cAMP) levels were measured in the aortas of rabbits fed a cholestrol rich diet for either 24 days (Group I), 86 days (Group II) or 86 days followed by 54 days of a normal diet (Group III). Aortic le vels of cholesterol and cholesterol esters, calcium and collagen and n oncollagen protein synthetic rates were also measured at each time per iod. Cyclic AMP levels were unchanged in the Group I animals but were significantly elevated in Groups II & III. Aortic levels of cholestero l and cholesterol esters, calcium and collagen and noncollagen protein synthetic rates were also significantly elevated in Groups II & II bu t unchanged in Group I. Since cAMP levels were not changed in Group I animals the increase in cAMP appears to be a later, adaptive change in response to the feeding of a cholesterol rich diet. The observation t hat cAMP levels are increased in response to cholesterol feeding is im portant since cAMP is known to be involved with a wide range of metabo lic functions, which may have a significant effect on the development of vascular disease.