Effect of human C-peptide on glucose transport in in vitro incubated human skeletal muscle.

Muscle specimens from the quadriceps femoris muscle were obtained from eight healthy subjects by means of an open muscle biopsy and prepared for in vitro incubation. C-peptide at 0.5, 1.0 and 2.5 nmol/l increased 3-0-methylglucose transport by 38% (NS), 64% (p less than 0.05), and 64% (p less than 0.05) respectively. Glucose transport increased 1.8-fold in the presence of 0.3 nmol/l of insulin (p less than 0.05). Glycogen content in muscle strips exposed to C-peptide at a concentration of 1 nmol/l increased significantly by 22% (p less than 0.05). In conclusion, C-peptide stimulates the rate of 3-0-methylglucose transport in in vitro incubated human skeletal muscle strips in a dose-response manner. These observations suggest that C-peptide may contribute to the regulation of carbohydrate metabolism in human skeletal muscle.