Scientific Background | C-peptide is the connecting segment excised when proinsulin is processed to insulin, and it is secreted from the beta cell in equimolar amounts with insulin. That stoichiometry is the basis of its long-standing clinical use: because C-peptide escapes the hepatic first-pass extraction that removes much of the insulin, it is the standard measure of endogenous insulin secretion, and it distinguishes endogenous production from administered insulin in a treated patient. The more interesting research question is whether C-peptide is merely a by-product. Work over two decades has argued that it is biologically active in its own right, with reported effects on erythrocyte Na+,K+-ATPase activity, nitric oxide production and microvascular blood flow in type 1 diabetes, and its potential role in diabetic nephropathy has been examined directly. This remains an area where findings have been debated rather than settled, and experimental design should account for that: appropriate controls and attention to peptide integrity matter more where the effect sizes under investigation are modest. This product is the human sequence, given as residues 55 to 89 of proinsulin. It is the variant for human immunoassay calibration, for work in human cells and tissues, and for studies where the measured analyte is the human peptide. The porcine sequence is offered separately as LT2107. |
References | 1. Wahren J, Ekberg K, Johansson J, et al. Role of C-peptide in human physiology. American Journal of Physiology (2000) 278:E759. Am J Physiol 2000;278:E759 2. Physiological effects and therapeutic potential of proinsulin C-peptide. American Journal of Physiology (2014). Am J Physiol 2014 3. Effects of proinsulin C-peptide on nitric oxide, microvascular blood flow and erythrocyte Na+,K+-ATPase activity in diabetes mellitus type I. Clinical Science (2000) 98:283. Clin Sci 2000;98:283 4. C-peptide: the missing link in diabetic nephropathy? PMC2827272 |
