C-peptide fragments stimulate glucose utilization in diabetic rats.
Studies of C-peptide cellular effects show that not only the full-length native peptide but also specific C-terminal fragments are biologically active in in vitro systems. In the present study, the effect of five C-peptide fragments and the native peptide on whole-body glucose turnover was studied in streptozotocin diabetic rats using the insulin clamp technique. Insulin was infused intravenously at 18 pmol kg(-1) min(-1) for 90 min and blood glucose concentration was clamped at 8 and 4 mM in diabetic and non-diabetic animals. A steady state was reached during the last 30 min of the study period. Rat C-peptide II and fragments comprising residues 27-31 and 28-31 were effective in augmenting glucose turnover in diabetic rats (+100% to 150%), while no significant effects were seen for segments 1-26, 11-19 and 11-15. The metabolic clearance rate for glucose during infusion of C-peptide or fragments 27-31 and 28-31 in diabetic rats was similar to that seen in non-diabetic animals. We conclude that C-terminal tetra- and pentapeptides, but not fragments from the middle segment of C-peptide, are as effective as the full-length peptide in stimulating whole-body glucose turnover in diabetic rats.
Sato
Y
Y
Research Centre of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan.
Oshida
Y
Y
Han
Y-Q
YQ
Morishita
Y
Y
Li
L
L
Ekberg
K
K
Jörnvall
H
H
Wahren
J
J
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D001835:Body Weight; D002096:C-Peptide / Q000008:administration & dosage*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D015309:Glucose Clamp Technique; D007262:Infusions, Intravenous; D007328:Insulin / Q000008:administration & dosage; D008297:Male; D008657:Metabolic Clearance Rate; D010446:Peptide Fragments / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D010446:Peptide Fragments