Endocrine and exocrine function of intrasplenic pancreatic autografts

A current technique of pancreatic islet autotransplantation utilizes only partially purified islets. After exposing minced whole pancreas to collagenase digestion, the pancreatic tissue is transplanted with no attempt to separate exocrine from endocrine tissue. The present study was undertaken to evaluate the exocrine and endocrine function of such pancreatic autografts. Six control dogs (group I), six pancreatectomized dogs that had undergone intrasplenic islet autotransplantation (group II), and three pancreatectomized dogs without transplants, to be referred to as 'nontransplanted' dogs (group III), were studied. The mean (± SEM) levels of fasting peripheral blood glucose were 68 ± 6, 87 ± 8, and 174 ± 22 mg/dl in groups I, II, and III, respectively. The mean (± SEM) levels of fasting portal vein insulin were 58 ± 25, 19 ± 4, and < 2.5 μU/ml in groups I, II, and III, respectively. Total insulin output following stimulation with glucose, secretin, and ceruletide was estimated. There were no significant differences between groups I and II in the total (0 to 90 minutes) and second-phase (10 to 90 minutes) insulin responses following glucose stimulation. Group II had a significant smaller first-phase (0 to 10 minutes) insulin output than had group I (P < 0.01) after glucose and ceruletide but not after secretin stimulation. No insulin output occurred in group III. The mean (± SEM) levels of fasting portal vein amylase were 830 ± 150, 275 ± 80, and 183 ± 76 Caraway units/dl in groups I, II, and III, respectively. There was no significant amylase response to secretin or ceruletide administration in any of the groups. These data suggest that the exocrine tissue content of pancreatic autografts is nonfunctioning, but that the transplanted islet tissue of maintaining fasting normoglycemia and of responding to physiologic stimuli.