Dietary branched-chain amino acids suppress the expression of pancreatic amylase mRNA in rats.

Regulators for pancreatic amylase were examined. Rats were fed ad libitum a 20% amino acid (AA) mixture diet (Con), a 60% AA diet (HA), a branched-chain amino acid (BCAA)-rich diet (BC), or a diet supplemented with AA other than BCAA (OA) for 7 d, or fed the Con, HA, BC diets or diets supplemented with individual BCAA. Activity and mRNA levels of pancreatic amylase in the BC and HA groups were lower than those in the Con and OA groups. Leucine and isoleucine contributed to these effects of the BC diet. The mRNA levels correlated with individual pancreatic BCAA concentrations but not with plasma insulin level. In conclusion, dietary BCAA, especially leucine and isoleucine, may reduce amylase mRNA and activity in rats.