Changes of function and metabolism of the pancreatic B-cell caused by amino acids and related compounds.

Evidence is presented that, to explain the insulin releasing capacity of L-leucine, b-BCH or alpha-ketoisocaproate (KIC), the following alternatives must be considered: 1. Interaction of the unchanged molecules with specific B-cell membrane receptors triggers insulin release. Stimulation of metabolism is a consequence of these events. 2. Primary enhancement of intramitochondrial hydrogen production triggers insulin secretion which could modulate metabolism. 3. Combination of mechanism 1 and 2: a) Additive effects of 1 and 2. b) Potentiation of 1 by 2. c) Potentiation of 2 by 1. 4. Different control of first phase or second phase of insulin release by 1, 2, or 3.