Biomaterial Database

Interaction of branched chain amino acids and keto acids upon pancreatic islet metabolism and insulin secretion. 1980

J C Hutton, and A Sener, and W J Malaisse

Insulin release evoked by 2-ketoisocaproate from isolated rat pancreatic islets was inhibited by L-valine, L-isoleucine, L-norvaline, and L-norleucine. The stereo-specificity of the inhibition and the finding that the decrease in secretory rate was correlated to the capacity of these amino acids to undergo transamination with the keto acid secretagogue suggested that a branched chain amino acid aminotransferase enzyme was the site of interaction of these substrates. The stimulation of transamination by these amino acids was accompanied by a decrease in the primary decarboxylation and oxidation of 2-ketoisocaproate in the tissue and a reduction in islet acetoacetate production. The oxidation of the amino acid substrate was slightly increased in the presence of 2-ketoisocaproate. Nevertheless, the oxidation rate of exogenous substrates and respiration were higher in the presence of 2-ketoisocaproate than when this substrate was combined with an amino acid. The action of 2-ketoisocaproate to increase the ratios of NADH/NAD+ and NADPH/NADP+, to enhance the uptake of 45Ca by islet tissue, and to promote proinsulin biosynthesis was also suppressed by the addition of branched chain amino acids to the incubation media. Radioisotopic uptake measurements suggested that many of these observations could be related to changes in the intracellular concentration of 2-ketoisocaproate in islet tissue.

UI	MeSH Term	Description	Entries
D007328	Insulin	A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).	Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
D007515	Islets of Langerhans	Irregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the PANCREAS among the exocrine acini. Each islet is surrounded by connective tissue fibers and penetrated by a network of capillaries. There are four major cell types. The most abundant beta cells (50-80%) secrete INSULIN. Alpha cells (5-20%) secrete GLUCAGON. PP cells (10-35%) secrete PANCREATIC POLYPEPTIDE. Delta cells (~5%) secrete SOMATOSTATIN.	Islands of Langerhans,Islet Cells,Nesidioblasts,Pancreas, Endocrine,Pancreatic Islets,Cell, Islet,Cells, Islet,Endocrine Pancreas,Islet Cell,Islet, Pancreatic,Islets, Pancreatic,Langerhans Islands,Langerhans Islets,Nesidioblast,Pancreatic Islet
D007651	Keto Acids	Carboxylic acids that contain a KETONE group.	Oxo Acids,Oxoacids,Acids, Keto,Acids, Oxo
D009243	NAD	A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)	Coenzyme I,DPN,Diphosphopyridine Nucleotide,Nadide,Nicotinamide-Adenine Dinucleotide,Dihydronicotinamide Adenine Dinucleotide,NADH,Adenine Dinucleotide, Dihydronicotinamide,Dinucleotide, Dihydronicotinamide Adenine,Dinucleotide, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide,Nucleotide, Diphosphopyridine
D009249	NADP	Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)	Coenzyme II,Nicotinamide-Adenine Dinucleotide Phosphate,Triphosphopyridine Nucleotide,NADPH,Dinucleotide Phosphate, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide Phosphate,Nucleotide, Triphosphopyridine,Phosphate, Nicotinamide-Adenine Dinucleotide
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D005260	Female		Females
D000078790	Insulin Secretion	Production and release of insulin from PANCREATIC BETA CELLS that primarily occurs in response to elevated BLOOD GLUCOSE levels.	Secretion, Insulin
D000597	Amino Acids, Branched-Chain	Amino acids which have a branched carbon chain.	Branched-Chain Amino Acid,Amino Acids, Branched Chain,Acid, Branched-Chain Amino,Acids, Branched-Chain Amino,Amino Acid, Branched-Chain,Branched Chain Amino Acid,Branched-Chain Amino Acids