Diurnal profiles of intermediary metabolites in insulin-dependent diabetes and their relationship to different degrees of residual B-cell function.

Diurnal profiles of blood metabolites, insulin and C-peptide were measured in 18 insulin dependent diabetics with less than 2-year duration of disease. Seventeen of the 18 patients had endogenous insulin secretion. A significant inverse correlation was found between mean C-peptide and mean blood glucose. Patients with maximal C-peptide equal to or above 0.30 pmol/ml had a better degree of control evaluated from mean blood glucose in spite of being treated with less insulin compared to patients with less B-cell function. The mean concentrations of alanine, lactate, glycerol and beta-hydroxybutyrate were not different in patients with CPR equal to or above 0.30 pmol/ml compared to patients with less CPR. The highest concentration in blood hydroxybutyrate for all the patients was seen in the fasting state, and the disappearance rate of blood hydroxybutyrate after breakfast was inversely correlated with the residual B-cell function. During the study period the mean insulin concentration in the diabetics and the normals was the same, but the brisk increase in insulin concentration related to meals was decreased or lost in the diabetics. Compared to normals the mean blood glucose, beta-hydroxybutyrate and glycerol were higher in the diabetics and the diurnal changes were grossly abnormal. No difference was found in alanine concentration and mean lactate concentration, but the increase in lactate seen after meals in normals was lost in the diabetics. The results confirm that other metabolites than glucose are abnormal in diabetics and that residual B-cell function has metabolic consequences for other metabolites than glucose during daily life conditions.