Insulin secretion from isolated pancreatic islets in the female rat. Short and long term oestradiol influence

An increase in the two phases of glucose-induced insulin response is observed after an oestradiol (E2) treatment or after a direct E2 action on the female rat perfused pancreas. To study such effects, experiments were carried out with isolated islets of Langerhans, and especially with a dynamic method : perifusion of the islets. The same long term E2 permissive effect was obtained with isolated islets submitted to a glucose stimulation. On the contrary, the direct E2 action seen in glucose-stimulated perfused pancreas was found neither with incubation tests, nor with perifusion studies, whatever the experimental conditions (E2 or glucose doses, exposure times, oestrous or spayed rats, 100 instead of 25 islets per perifusion chamber). The differences between isolated islets of Langerhans and the whole perfused pancreas preparation are discussed.