Abstract

It is now well established that the proinsulin connecting peptide(C-peptide) is released into blood from the beta cells together with insuline. Assay of serum C-peptide, as a substitute for the insulin assay, provides an additional means to evaluate the endocrine function of the pancreatic beta cells even in the presence of circulating insulim antibody. The measurement of plasma C-peptide could not provide a accurate reflection of various physiologic conditions. But,because of the relatively high urinary clearance of C-peptide and the absence of signficant herpatic uptake, urinary C-peptide measurement might provide a accurate reflection of B-cell secretory activity during 24 hours. We measured 24 hours urine C-peptide excretion in the normal control, NIDDM, inflection diseas, insulinoma, hemochromatosis and the chronic renal failure. The results were as folIows: 1. In the normal Korean, the 24 hours urine C-peptide was 52 +-18 pg/gm creatinine. 2. In patients with NIDDM, the urine C-peptide was not different from that of normal subjects(53+- 14 pg/gm cr). 3. The urine C-peptide was markedly increased in response to infection, although the urine C-peptide response to infection in patients with NIDDM(124+- 38 pg/gm cr) was significantIy lees than the non-diabetic patients(155+- 58 pg/gm cr ), 4. The urine C-peptide was decreased in the patient with hemochromatosis(44 pg/gm cr) but markedly increased in the patient with insulinoma (132 pg/gm cr) 5. In patients with chronic renaI failure, the urine C-peptide was decreased(2.3+-1.1pg/gm cr)