This report describes a comparative examination of adult rat pancreatic islets maintairned in either monolayer or free-floating cultures.
The insulin secretion of freshly collagenase-isolated rat islets and islets which had been maintained in either free-floating or monolayer cultures for two weeks was measured during incubation in a medium containing 5.5 mM D-glucose, then in a 16.7 mM D-glucose concentration, and finally in a combination of 16.7 mM D-glucose and 3-isobutyl-1-methylxanthine (IBMX, 1.0 mM).
The insulin secretion of the monolayer islet culture was markedly enhanced by stimulation of glucose at the high concentration and in combination with IBMX. In addition, the monolayer islets had the highest insulin content.
This data suggests that the most favorble conditions for long-term survival of isolated islets in culture may be obtained when the islets form a monolayer.