Abstract
The methionine (Met) action on serum cholesterol (Ch) and lipoprotein profiles was studied by varying the dietary carbohydrate sources in normal, hepatoma (AH109A)-bearing and Ch-loaded Donryu rats fed on 20% casein diets for 2 weeks. In normal rats, Met (1.8%) addition to a 20% casein diet containing a sucrose-starch (1:3) mixture increased HDL-Ch without affecting (VLDL + LDL)-Ch, and resulted in a significant reduction of the (VLDL + LDL)-Ch/HDL-Ch ratio (atherogenic index, AI), while Met showed no significant influence on them under dietary condition of sucrose alone or starch alone. In hepatoma-bearing rats, Met (1.2%) also had a significant influence only when the sucrose-starch mixture was used as the dietary carbohydrate source, the amino acid reducing AI by both suppressing the hepatoma-induced elevation in (VLDL + LDL)-Ch and increasing HDL-Ch. In Ch-loaded rats, however, Met (0.75 %) exerted no significant influence under the dietary carbohydrate source of the sucrose-starch mixture, but this amino acid significantly decreased (VLDL + LDL)-Ch without affecting HDL-Ch, and hence reduced AI under the dietary condition of sucrose alone or starch alone. These results suggest that dietary carbohydrates modulate the Met action on cholesterolemia depending on the absence or presence of dietary Ch, and that Met is essentially antiatherogenic from the aspect of lipoprotein profiles when the amino acid expresses significant influence on cholesterolemia in Donryu rats.
