Immunohistochemical localization of insulin-like materials in antral gastric mucosa and intestinal epithelial cells of the turtles Chrysemys dorbigni and Phrynopshilarii

Immunoreactive insulinwas demonstrated immunohistochemically with antibodies to human and porcine insulin by the avidin-biotin-peroxidase complex method in open-type gastrointestinal cells from sections of the antral stomach and of the upper, midle and lower intestine of the turtles Chrysemys dorbigni and Phrynops hilarii.In both species the concentration of cells positive for insulin-like material was higher in the gastric antrummthan in the gut.The localization of insulin-like material in gastrointestinal mucosal cells of turtles is an unusual finding among vertebrates, because the insulin-containing cells migrate from the mucosal epithelium of the intestine early in vertebrate evolution to the acinar pancreas.The chemical nature of the gastrointestinal insulin-like material and its physiological role remainm to be determined

Glycemia and immunohistochemical changes in the endocrine pancreas of the turtle Chrysemys dorbigni treated with streptozotocin

The diabetogenic action of streptozotocin (SZ) was inbestigated in the turtle Chrysemys dorbigni after a 1-or 14-day fast. SZ (130 or 250 mg/Kg) was inected intravenously, and blood glucose and plasma insulin were measured. Pancreatic endocrine cells were stained immunohistochemically by the immunoperoxidase avidin-biotin-peroxidase complex method. Only 14% of the SZ-treated turtles showed hyperglycemia. Prolonged fasting did not increase the percentage of hyperglycemic animals. In control turtles, insulin (ß-, glucagon (alfa)-and somatostatin (delta)-immunoreactive cells were detected in increasing order of frequency. The qualitative changes seen in cells from the hyperglycemic SZ-treated turtles were more evident in ß and delta cells