Stimulatory effect of serum from diabetic patients on insulin release from mouse pancreatic islets maintained in tissue culture

Abstract

Summary. Islets of Langerhans from NMRI-mice were kept for one week in tissue culture in medium supplemented with human serum obtained from either normal healthy subjects or newly diagnosed juvenile diabetic patients before insulin treatment. Islets cultured in diabetic serum released more insu, lin than islets cultured in normal serum, whether tissue culture medium 199 with 5.5-8.3 mmol/1 glucose and 10% serum, or culture medium RPMI 1640 with 11 mmol/1 glucose and 0.5% serum were used. Islets kept for one week in culture with diabetic serum did not show any decrease in DNA content or glucose induced insulin secretion and biosynthesis. It is concluded that serum from newly diagnosed insulindependent diabetic patients stimulates insulin release from isolated mouse islets kept in tissue culture. The underlying mechanism is unknown.

Complement-fixing Islet Cell Antibodies from Some Diabetic Patients Alter Insulin Release In Vitro

“…Some possible explanations are: the presence of an ongoing cytolytic IRI release in basal medium, a nonspecific stimulation of the remnant beta-cells by some cytolytic byproducts (e.g., amino acids), and the presence of some paradoxically stimulating beta-cell factors). 27 This high basal release after incubation with some IDDM sera was not observed in preliminary perfusion experiments.…”