Effects of pancreas transplantation on insulin secretion in the rat during ingestion of varying glucose loads

Following alloxan induced diabetes in rats, transplantation of neonatal pancreases under the kidney capsule was successfully carried out. The insulin response to oral ingestion of 150 and 750 mg of glucose was studied. The responses in controls and in rats 40 days after transplantation demonstrated a load-dependent increment of plasma insulin responses which was not related to the similar glucose responses. In control rats a part of the insulin response had occurred at 1 min, i.e. 2 min before the rise in blood glucose. After transplantation in the absence of this nervously triggered response, blood glucose rose faster than in control rats from 3 to 5 min after start of ingestion (p < 0.01). In non-transplanted rats regenerating a part of their original pancreas within one week, glucose intolerance was seen 10 min after glucose ingestion, probably due to the lack of adequate secondary phase release. This study shows that maintenance of a normal glucose tolerance curve to glucose ingestion depends on at least two factors. First, an anticipatory nervously triggered insulin secretion. Second, a load dependent humoral potentiation of glucose stimulated insulin release