The Hypercholesteremic and Atherogenic Properties of Various Purines and Pyrimidines

Abstract

The hypercholesteremic and atherogenic properties of RNA, DNA, four purines, and three pyrimidines were assayed in rats fed moderately atherogenic diets for 10 weeks. It was found that either RNA or DNA supplementation alone favors a mild increase in hypercholesteremic response and cardiovascular sudanophilia. When RNA and DNA were combined in such diets, the level of cardiovascular sudanophilia was reduced to levels seen among the control rats. Among the four purines studied, adenine was found to be the most atherogenic and hypercholesteremic. In addition, these animals displayed severe obstructive renal lesions and medionecrosis of the aorta and its branches, including the coronary arteries. The aortic lesions were associated with aneurysmal dilatation, fibrous intimal plaque formation, and lipid deposition. On the other hand, the rats fed either guanine, uric acid, or xanthine all demonstrated significant elevations in the serum cholesterol response and only mild increases in the amount of cardiovascular sudanophilia without the above renal damage or vascular necrosis. Among the rats fed pyrimidines, uracil treatment resulted in a marked hypercholesteremia and cardiovascular sudanophilia. The nature of these changes as supported by thyroidal hyperplasia is reminiscent of the changes seen among rats treated with dietary thiouracil. This uracil effect on the thyroid therefore may account for the singular properties noted in this pyrimidine. The rats fed thymine demonstrated a mild increase in hypercholesteremia and cardiovascular sudanophilia, while the cytosine group's response was not significantly higher than the control rats. Significant thyroidal changes were not noted among these latter two pyrimidine groups.