STUDIES WITH AUTOTRANSPLANTED OVINE PANCREAS - GLUCAGON AND INSULIN SECRETION

Basic studies on the secretion of glucagon and insulin by the ovine pancreatic autotransplant in the neck are described. Of the 17 transplants in the series all secreted glucagon; 3 failed to secrete insulin in detectable amounts. The longest surviving transplant actively secreted both hormones 3 yr after transplantation, and 5 other transplants were functional and the animals healthy after 16 mo. Exocrine secretion disappears shortly after transplantation. Sodium butyrate and alanine each promoted the secretion of both hormones by the transplant. Glucagon failed to promote insulin secretion by the transplant, although it apparently stimulated the ovine in situ pancreas. The immediate (presumably direct) effect of insulin was to inhibit transplant glucagon secretion. Hypoglycemia induced by peripheral insulin administration failed to stimulate glucagon secretion by the transplant, although it did promote glucagon secretion by the ovine in situ pancreas. Heparin did not markedly suppress basal transplant secretion of either glucagon or insulin. Phasic response patterns occurred with both hormones during long butyrate perfusions, although 1st-phase responsiveness was not a constant feature. In 1 trial, 1st-phase responses fell off with repeated short butyrate infusions. Glucagon and insulin secretory patterns in response to butyrate were remarkably alike, suggesting a common mechanism. Loss of specific functions by the ovine pancreas after transplantation is discussed.