FURTHER STUDIES ON 5‐HYDROXYTRYPTAMINE TRANSPORT IN PANCREATIC ISLETS AND ISOLATED β‐CELLS

Abstract

The transport mechanism for 3H‐labelled 5‐hydroxytryptamine (5‐HT) in isolated pancreatic islets of non‐inbred ob/obmice was further characterized. Isolated β‐cells accumulated 5‐HT to the same degree and with the same Na+‐dependence as whole islets. Imipramine inhibited the uptake in a concentration‐dependent way. Reserpine did not affect the uptake or efflux rates. Glucose stimulation of insulin secretion did not affect the uptake rate. It is concluded that the observed islet uptake of [3H]‐5‐HT represents an intracellular accumulation by the β‐cells. Mechanisms at the level of the plasma membrane may be rate‐limiting for this process. 1981 British Pharmacological Society