ISOLATION OF FUNCTIONAL GLUCAGON ISLETS OF LANGERHANS FROM THE CHICKEN PANCREAS

Two types of islets of Langerhans are present in the avian endocrine p ancreas: glucagon islets (A-islets) and insulin islets (B-islets). Isl ets from the chicken pancreas were isolated by ductal injection of col lagenase, enzymatic digestion, atraumatic dispersion of the digests at an appropriate time, and nylon mesh filtrations. A- and B-islets were identified by immunohistochemistry and radioimmunological quantificat ion of insulin and glucagon. Dithizone-positive islets proved to be mo stly of the A-type by immunostaining, and radioimmunological measureme nts: islets from the cranial half of the body of the pancreas were alm ost pure (95%) glucagon islets (0.454 +/- 0.027 pmol glucagon and 0.02 3 +/- 0.005 pmol insulin per islet). Increasing the glucose concentrat ion in the incubation medium from 14 to 42 mM decreased glucagon relea se, demonstrating that the alpha-cells maintained their glucose sensit ivity after isolation. (C) 1998 Academic Press.