[Insulinotropic factors in health and disease]

Reviews in brief the studies of the effects of some non-glucose regulators of various origins on pancreatic insulin secretion mediated by endocrine, paracrine, and neurocrine mechanisms, carried out in this laboratory. Model experiments with primary monolayer cultures of isolated islet cells have helped demonstrate a direct insulinotropic effect of STH, TRH, C-terminal tetrapeptide cholecystokinin, opioid peptides and blood plasma of patients with insulin-dependent diabetes mellitus. The findings evidence that the insulinotropic effect of the blood serum of patients with type I diabetes may be associated with both stimulation and suppression of the functional activity of the cultivated islet cells. This latter type of effect influences the basal and glucose-stimulated secretion of insulin. The destructive effect of the plasma of patients with insulin-dependent diabetes on the function of islet cell culture is confirmed by the presence of autoantibodies to islet cell surface antigens in the plasma of 53-55% of the examined patients and by a cytotoxic effect in 45% of cases.