Roles of insulin and glucose in the regulation of plasma FFA in the duck. I. In the absence of pancreatic glucagon.

The present study was undertaken to determine how free fatty acid (FFA) release by adipose tissue can occur in the absence of pancreatic glucagon, the most potent lipolytic hormone in the duck. Two possible explanations have successively been investigated. Replacement therapy experiments showed that glucose uptake was implicated in the phenomenon; indeed, when pre-operative insulin and glucose levels were restored after total pancreatectomy, plasma FFA progressively fell to a level significantly lower than the pre-operative value. The same effect was observed when the ducks were kept in a continuous state of hyperglycaemia, whereas "normal" levels of insulin or glucose alone were shown to be ineffective. On the other hand a compensatory mechanism for the lack of glucagon, by other lipolytic agents [with the intestine or the anterior pituitary as possible sources] has been excluded by associating the removal of these two organs with pancreatectomy. These experiments suggest that the lack of pancreatic glucagon induced by total pancreatectomy is essentially masked by a failure in glucose uptake due to the operation.