Pathological Effects of Excessive Methionine in the Diet of Growing Rats

Abstract

One month after feeding excessive amounts of L- or D-methionine to 30-day-old rats of both sexes, histological changes were observed in the spleen, pancreas, and liver. All of these changes were reversed on continuation of the feeding of the excessive methionine diets, and after three months, the histological appearance of the organs was normal even following 9 months of continuous feeding. Inhibition of weight gain was roughly proportional to the amount of excess methionine in the diet, and after 9 months of feeding 4% of methionine in the diet, the rats of both sexes did not reach the full weight of the control rats reach by the latter in about 4 months. The utilization of the methyl group of methionine for the in vivo synthesis of tissue choline, creatine, and methionine is appreciably limited in the young rat, and this observation may be related to the age-limited ability of the rat to prevent the temporary organ damage by the excessive methionine in the diet. The histological changes induced by small amounts of ethionine and the reversibility of these changes in the organs of rats fed methionine, in contrast with those induced by ethionine, were discussed in relation to biochemical alterations in the organs of animals fed methionine or ethionine.