Effects of millet grain administration on lipid metabolism in type 2 diabetic db/db mice

Abstract

We investigated the effects of an oral administration of daily millet grain feed in type 2 diabetic mice. Mice ?C57BL/KsJ-leprdb/lepr db, db/db?were fed a diet containing 20% proso millet?PM?, Japanese barnyard millet?BM?, or adlay ?AD? powder based on AIN-93G for 21 days. As a result, the HbA1c concentration of whole blood was lower in the diabetic PM- and BM-fed groups than in the diabetic control ?AIN-93G? group. Concentrations of hepatic lipid parameters, such as lipids, total cholesterol, and triglycerides in the BM- and AD-fed groups were lower than those in the diabetic control group. In addition, the concentration of bile acid in feces was higher in the diabetic BM- and AD-fed groups than in the diabetic control group. Although gene expression of cholesterol synthesis enzymes such as 3-hydroxy-3-methylglutaryl- CoA reductase?HMG-CoAR?was not different between the diabetic mice groups, that of bile acid synthesis enzymes such as cholesterol 7 α-hydroxylase ?CYP7Awas higher in the diabetic BM- and AD-fed groups than in the diabetic control group. These results suggest that PM and BM grains have hypoglycemic activity, and BM and AD grains have hypolipidemic activity. The effect of improved lipid metabolism by BM and AD grains is attributed to the acceleration of bile acid synthesis in liver along with its excretion into feces.