The effects of age and folate intake on the activities of four methionine cycle enzymes and plasma homocysteine levels in the rat

Homocysteine is considered an independent risk factor for heart disease. Hyperhomocysteinemia has been positively correlated with advancing age. Elevated homocysteine levels occur in humans with inadequate intake several B vitamins. Aging may be a factor as well. This work examines the effects of age and folate intake on serum homocysteine and four methionine cycle enzymes.; The study uses a 3 x 3 factorial design with male rats at three ages and three levels of folate intake. The feeding period was seven weeks with tissues collected at the end of the feeding period.; Aging appeared to have no effect on serum homocysteine in animals fed either 2 ppm or 10 ppm dietary folate. Significantly elevated levels were seen on the no added folate diet. Generally, enzyme activity increases from young to adult animals and then decreases into older age.