CP and type 1 diabetes mellitus: Additionally, increasing evidence suggests that C-peptide (CP) exerts a range of effects on metabolism, neuroprotection and anti-apoptosis (25–27), including the Na+/K+- ATPase activity, endothelial nitric oxide synthase, expression of neurotrophic factors, and the regulation of molecular species underlying the degeneration of the nodal apparatus in nerves of T1DM (25, 26).