Insulin release from isolated human fetal pancreatic islets.

Pancreases were obtained from five human fetuses 12 to 16 weeks old. The islets of Langerhans were isolated with collagenase, and then incubated with buffer, glucose, tolbutamide, or glucagon added to the medium. The insulin released into the medium was measured by immunoassay. Glucagon produced the only significant increase above base line; glucose and tolbutamide failed to enhance secretion of insulin. The data suggest that isolated human fetal islets of this gestational age develop responsiveness to glucagon earlier than to glucose or tolbutamide.