The use of insulin in the production of L-leucine-induced hypoglycemia in normal dogs.

The initial observation of Cochrane, Payne, Simpkiss and Woolf, who described the hypoglycemic effect of L-leucine in certain patients with idiopathic infantile hypoglycemia (1), has been repeatedly confirmed. (2-6). L-leucine has also produced a hypoglycemic effect in certain patients with functioning islet cell tumors of the pancreas (7). Not all patients with these clinical syndromes respond to leucine, and the phrase "leucine-sensitive" has been used to designate those patients in whom a hypoglycemic response to leucine can be demonstrated. Previous studies have been unable to demonstrate a lowering effect of L-leucine on blood glucose in normal subjects, and experimental studies of leucine-induced hypoglycemia have of necessity been limited to a few patients with relatively rare diseases. Since hyperinsulinism or hypoglycemia, or both, appeared to be possible necessary prerequisites for the induction of leucine hypoglycemia, an attempt was made to produce experimentally "leucine sensitivity" in normal dogs by pretreatment with insulin. The present report describes the lowering effect on blood glucose that follows L-leucine administration to normal dogs treated with insulin in a variety of ways. In addition, the effect of L-leucine on the magnitude of femoral arteryfemoral vein glucose concentration differences after acute insulin-induced hypoglycemia is discussed.