C-peptide is co-secreted with insulin and has generally been considered not to possess
biological activity. However, several recent studies during the last five years have
demonstrated that administration of C-peptide in physiological amounts to type 1 diabetes
(IDDM) patients on a short term basis (1 - 3 h) results in decreased glomerular hyperfiltration,
augmented glucose utilization and improved autonomic nerve function. More prolonged
administration (1 - 3 months) of C-peptide to IDDM patients is accompanied by improvements
in both renal function (diminished microalbuminuria) and autonomic and sensory nerve
function. Both in vitro and in vivo data indicate that C-peptide may have a role in the regulation of insulin secretion.
C-peptide's mechanism of action is not known but it may be related to its ability
to stimulate Na+,K+-ATPase, activity, probably by activating a receptor coupled to a pertussis toxin-sensitive
G-protein with subsequent activation of Ca2+-dependent intracellular signaling pathways. In conclusion, the combined findings
indicate that C-peptide is a biologically active hormone. The possibility that C-peptide
therapy in IDDM patients may be beneficial should be considered.
Diabetes mellitus - IDDM - Glomerular hyperfiltration - Neuropathy - Insulin secretion
- Microalbuminuria - Na+,K+-ATPase