Characterization of secretory and morphologic properties of primary cultured endocrine cells from porcine pancreata.

Abstract

We characterized morphologic and secretory properties of porcine pancreatic endocrine cells in primary culture obtained by autolytic preparation without any exogenous proteolytic enzymes. The endocrine cells exhibited a neuron-like shape, and insulin granules were accumulated at the terminal of the processes. Thus derived endocrine cells survived in culture medium containing nicotinamide and remained sensitive to glucose for at least 6 weeks after preparations. The cells responded well to physiologic concentrations of glucose, and high K+ depolarization and the antidiabetic sulfonylureas, tolbutamide, and glibenclamide also elicited the release. With high glucose, insulin release was markedly potentiated by forskolin, glucagon, glucagon-like peptide-1, and arginine and inhibited by somatostatin, the Ca2+ channel blocker nitrendipine, and the ATP-sensitive K+ channel opener diazoxide. Epinephrine had dual effects on the release by glucose; enhanced within a low nanomolar range and inhibited at 1 micromol/L. However, the cells were unresponsive to leucine. Such secretory sensitivities to nutrients, hormones, and pharmacologic agents, and long survival rate (as long as 5-6 weeks) of these cells suggest to us therefore that derived endocrine cells may be useful for xenotransplantation of pancreatic beta cells for treatment of insulin-dependent diabetes mellitus.