Stimulaiton of insulin biosynthesis in isolated mouse islets by L-leucine, 2-aminonorbornane-2-carboxylic acid and alpha-ketoisocaproic acid.
An immune binding technique was used for measuring the effects of certain amino acids on the rate of insulin biosynthesis. [13H]phenylalanine served as the radioactive precursor for insulin synthesized by isolated mouse pancreatic islets. L-Leucine was found to stimulate the insulin biosynthesis and this effect was observed already at a physiologic concentration in contrast to the much higher concentrations needed to stimulate insulin secretion in vitro. Furthermore, it was found that 2-aminonorbornane-2-carboxylic acid and alpha-ketoisocaproic acid shared with glucose and L-leucine the ability to stimulate insulin biosynthesis. In contrast, L-alanine, L-arginine adn D-leucine had no stimulatory effect in the absence of glucose, while in the presence of 5 mM glucose L-arginine decreased and L-alanine increased the incorporation rate of tritiated phenylalanine. The fact that many of those compounds which stimulated insulin biosynthesis have also been shown elsewhere to be metabolized by the B-cells supports the view that the rate of insulin biosynthesis may be substrate dependent.
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D066298:In Vitro Techniques; D007328:Insulin / Q000096:biosynthesis*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007651:Keto Acids / Q000494:pharmacology*; D007930:Leucine / Q000096:biosynthesis / Q000494:pharmacology*; D008297:Male; D051379:Mice; D010649:Phenylalanine / Q000378:metabolism; D011384:Proinsulin / Q000096:biosynthesis
D000596:Amino Acids; D007328:Insulin; D007651:Keto Acids; D010649:Phenylalanine; D011384:Proinsulin; D007930:Leucine