Effects of alpha-ketomonocarboxylic acids upon insulin secretion and metabolism of isolated pancreatic islets.
In perifused isolated pancreatic islets alpha-ketoisocaproic acid (KIC) or alpha-ketocaproic acid (KC) induced a high insulin secretion rate and a steep increase of the fluorescence of reduced pyridine pyridine nucleotides [NAD(P)H] which fell again to almost prestimulatory levels 6 min after medium change. Insulin release in response to alpha-ketooctanoic (KO) acid started slowly and was accompanied by a decrease of the NAD(P)H-fluorescence trace. Beta-phenylpyruvate which is known to initiate insulin release also caused a fluorescence decrease. Alpha-keto-isovaleric (KIV) acid or pyruvate had no significant effects upon insulin secretion or NAD(P)H-fluorescence. In contrast to l-leucine, l-norleucine or l-valine did not enhance insulin release or fluorescence of NAD(P)H. KIV, alpha-keto-beta-methylvaleric acid (KMV), KIC and KC raised the production their corresponding amino acids by islet cells. From these results it is concluded that alpha-ketomonocarboxylic acids as such trigger insulin release by acting upon receptor sites which differ from those occupied by amino acids.
D000596:Amino Acids / Q000096:biosynthesis / Q000494:pharmacology; D000818:Animals; D002208:Caproates / Q000494:pharmacology; D002210:Caprylates / Q000494:pharmacology; D005260:Female; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000201:enzymology / Q000378:metabolism*; D007651:Keto Acids / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008820:Mice, Obese; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010667:Phenylpyruvic Acids / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology; D011773:Pyruvates / Q000494:pharmacology; D014631:Valerates / Q000494:pharmacology
D000596:Amino Acids; D002208:Caproates; D002210:Caprylates; D007328:Insulin; D007651:Keto Acids; D010667:Phenylpyruvic Acids; D011422:Propionates; D011773:Pyruvates; D014631:Valerates; D009243:NAD; D009249:NADP