Effects of Co-administration of Carbohydrate and Fat on Insulin Secretion and Muscle Glycogen Resynthesis after Exercise in Mice

Abstract

For the purpose of developing a novel method to promote muscle glycogen recovery, we examined the effects of co-administration of carbohydrate and fat on insulin secretion and muscle glycogen resynthesis after exercise in C57BL/6J mice. In Experiment 1, non-exercised mice were orally administered solution containing either glucose alone （2 mg/g BW） （CHO group） or glucose plus rapeseed oil （2 mg/g BW） （CHO-FAT group）．Blood sample were collected from tail vein and plasma glucose, insulin and glucose-dependent insulinotropic polypeptide （GIP） levels were determined. Compared with the CHO group, the CHO-FAT group had significantly higher plasma insulin and lower glucose levels after the administration （p<0.05）．Furthermore, Plasma GIP concentration was significantly higher in the CHO-FAT than CHO group （p<0.001） and was significantly associated with plasma insulin concentration （p<0.001）．In Experiment 2, mice performed an acute bout of 30-min swimming exercise and were then orally administered as in the Experiment 1. At 1 h after the administration, muscle glycogen content in hindlimb muscle was significantly higher in the CHO-FAT than CHO group. These results suggest that co-ingestion of carbohydrate and fat stimulates insulin secretion via gut-derived GIP and promotes muscle glycogen resynthesis after exercise in mice.