C-peptide determination in the choice of treatment in diabetes mellitus

Abstract
Koskinen P, Viikari J, Irjala K, Kaihola H-L, Seppälä P. C-peptide determination in the choice of treatment in diabetes mellitus. Scand J Clin Lab Invest 1985; 45: 589-597. The predictive value of the intravenous glucagon test in assessing the requirement of insulin therapy in diabetes mellitus was evaluated in 105 adult diabetics. Basal and stimulated C-peptide concentrations and increments of C-peptide concentration were examined separately among newly and previously diagnosed diabetics. The poststimulatory C-peptide concentration of 0.6 nmol/1 (Novo, antibody M 1230) proved to be the most reliable basis for the choice of therapy. Adequate therapy could have been assessed in 70 cases (67%) without glucagon stimulation. To derive maximal information of plasma C-peptide concentrations, a biphasic scheme of the use for C-peptide determinations and glucagon stimulation is presented. Basal and stimulated C-peptide levels of insulin-requiring diabetics correlated negatively with the duration of diabetes but they did not correlate with the relative body weights. Basal and stimulated C-peptide levels of non-insulin-requiring diabetics did not correlate with the duration of diabetes, but they correlated positively with the relative body weights.