The purpose of this study is to determine how glucose uptake and glycogen turnover are related in vivo in the heart. Ketamineanesthettzed fasted rats were hepatic-occluded for 20 min. During the occlusion, the rats were infused intravenously with saline (group 1), insuiin at a rate of 10 mU min-1 (group 2), or insulin at the same rate plus glucose at a rate of 20.4 μmol-min-1. The infusion regimes were known to result in up to 30-fold differences in whole-body glucose utilization Glucose uptake was determined by the phosphorylation of [14C]-2-deoxyglucose, and glycogen synthesis by the incorporation of [3-3H)-glueose into glycogen in the heart. Both glucose uptake and glycugen synthesis in the heart were found to peak in group 2, in spite of a further increase of 5-fold in whole-body glucose utilization in group 3. While the mass of glycogen was found to increased only 0-33%. the incorporation of [3-3H]-glucose into cardiac glycogen in the two insulin-treated rats was found to increase 28 to 59-fold. The isotopic enrichment in cardiac glycogen indicates increases in glycogen turnover Thus, our data suggest that glycogen turnover and glucose uptake are closely associated in vivo in the heart.
|Publication status||Published - 1997|
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)
- Biochemistry, Genetics and Molecular Biology(all)
- Cell Biology