survival and function of purified islets in the omental pouch site of outbred dogs the aims of this study were to devise an omental pouch site for islet implantation in a preclinical large animal and to compare the function of islets engrafted to this site with islets implanted into the spleen highly purified islets were isolated from outbred mongrel dogs then grafted into totally pancreatectomized outbred recipients autografts of islets were implanted into a greater omental pouch group gp 1 n 12 or into the spleen by venous reflux gp 2 n 12 allografts of single donor islets were implanted into the omental pouch gp 3 of dogs that received csa n 9 or untreated controls n 3 the threshold islet mass that consistently reversed diabetes in gp 1 was 10 microliterskg which exceeded by 25fold that required in gp 2 normoglycemia was induced and maintained for 2 months in 6 gp 1 and 8 gp 2 dogs at ivgtt the k value decline in glucose min was 13 04 in gp 1 versus 15 02 in gp 2 p 02 peripheral venous insulin levels were significantly lower p 10 microliterskg were initially normoglycemic grafts of untreated controls failed at 42 18 days in 1 csatreated dog the graft failed for technical reasons normoglycemia persisted in the other 8 for 10 15 and 21 days and in 5 instances for 30 days when csa therapy was stopped at 30 days normoglycemia persisted for 34 95 days we conclude that purified islets restore normoglycemia after implantation into the omental pouch of diabetic dogs compared with intrasplenic islet implantation an increased graft volume is required and insulin levels are lower