Insulin Release from Monolayer Culture of Adult Rat Pancreatic Islets Using a Perifusion System

The dynamics of insulin secretion were studied in monolayer cultures of adult rat pancreatic islet cells. Free cells were dissociated from adult rat pancreatic islets by the enzymatic dispersion method with minor modifications and were cultured on 25 mm-round plastic cover slips. The cells were incubated for the first three days in tissue culture medium 199(TCM 199) containing 0. 1 mM 3-isobutyl-l-methylxanthine to promote monolayer formation and were then maintained in a functional state in growth medium (RPMI 1640) for two weeks. The monolayer culture consisted mainly of B cells as identified by immunohistochemical staining. A small number of A, D and PP cells of pancreatic islets were also distinguished in the culture. After 14 days of culture, the culture plate was placed in a Rose chamber through which the medium was pumped and from which the effluent was collected at various time intervals for insulin determination. It was observed that the insulin secretion from the adult rat pancreas induced by glucose is characterized by an early phase of rapid onset and a late phase both of short duration, that rapidly increased and came to a plateau as long as the stimulus was applied. This result indicates that the monolayer culture of adult rat pancreatic islets is a potential I method for supplying the hybrid artificial endocrine pancreas.