INTERACTIONS BETWEEN CARNOSINE AND VITAMIN-E IN MAMMARY-CANCER RISK DETERMINATION

Carnosine (beta-alanyl-histidine) is found in meats at concentrations as great as 0.35% of wet weight and is an effective antioxidant in in vitro systems though its role in vivo is unclear. Since antioxidant st atus has been shown to affect risk for carcinogen-induced mammary canc er we conducted a 2x2 factorial experiment assessing the effect of die tary vitamin E (0 or 50 ppm) and carnosine (0 or 875 ppm) on 7,12-dime thylbenz[a]anthracene (DMBA) induced mammary cancer in 55 day old fema le Sprague-Dawley rats. The diets had no significant effect on body we ight gain or organ weight at termination of the experiment 24 weeks fo llowing carcinogen administration. As expected, feeding the vitamin E (E) deficient diets resulted in significantly depressed serum and tiss ue E levels while there was a trend towards increased plasma malondial dehyde levels in E deficiency. Erythrocyte hemolysis was also signific antly increased by E deficiency. Carnosine supplementation significant ly increased E levels in liver and heart, but not in skeletal muscle, serum, or erythrocytes. Dietary carnosine significantly influenced car nosine. concentrations in liver but not in heart or skeletal muscle; d ietary carnosine also significantly elevated histidine concentrations in heart and skeletal muscle but not in serum or in liver. Carnosine s upplementation to E deficient rats resulted in a significant increase in tumor latency while non-significantly affecting tumor burden and tu mor incidence. Thus, carnosine appears to contribute to the overall an tioxidative system, and-its supplementation in the diet affects mammar y cancer risk in the DMBA model. (C) 1998 Elsevier Science Inc.