Mechanisms underlying the effects of 5-hydroxytryptamine and 5-hydroxytryptophan in pancreatic islets. A proposed role for L-aromatic amino acid decarboxylase. 1983

P Lindström, and J Sehlin

Microdissected pancreatic islets of noninbred ob/ob mice were used in studies of 5-hydroxytryptamine (5-HT) and 5-hydroxytryptophan (5-HTP) effects on insulin release. The potentiating effect of 4 mM L-5-HTP on glucose-induced insulin release was inhibited by the decarboxylase inhibitors benserazide (100 microM), alpha-monofluoromethyldopa (10 or 100 microM), carbidopa (50 or 500 microM), and NSD 1015 (5 or 50 microM). Activation of L-aromatic amino acid decarboxylase by DL-m-tyrosine (4 mM) or DL-o-tyrosine (4 mM) potentiated glucose-induced insulin release, whereas L-dopa (4 mM) inhibited it. Glucose oxidation was unaffected by L-5-HTP but slightly stimulated by 5-HT. Glucose-induced efflux of 33Pi was reduced by 5-HT but not affected by 5-HTP. These results are compatible with the ideas that 5-HT inhibits glucose-induced insulin release by affecting early steps in the beta-cell stimulus-secretion coupling and that 5-HTP-potentiation of insulin release is probably mediated by the decarboxylase activity but is independent of the 5-HT formed.

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
D008820 Mice, Obese Mutant mice exhibiting a marked obesity coupled with overeating, hyperglycemia, hyperinsulinemia, marked insulin resistance, and infertility when in a homozygous state. They may be inbred or hybrid. Hyperglycemic Mice,Obese Mice,Mouse, Hyperglycemic,Mouse, Obese,Hyperglycemic Mouse,Mice, Hyperglycemic,Obese Mouse
D009765 Obesity A status with BODY WEIGHT that is grossly above the recommended standards, usually due to accumulation of excess FATS in the body. The standards may vary with age, sex, genetic or cultural background. In the BODY MASS INDEX, a BMI greater than 30.0 kg/m2 is considered obese, and a BMI greater than 40.0 kg/m2 is considered morbidly obese (MORBID OBESITY).
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
D006916 5-Hydroxytryptophan The immediate precursor in the biosynthesis of SEROTONIN from tryptophan. It is used as an antiepileptic and antidepressant. 5-HTP,Hydroxytryptophan,Oxitriptan,Oxytryptophan,Tryptophan, 5-Hydroxy-,5 Hydroxytryptophan,5-Hydroxy- Tryptophan,Tryptophan, 5 Hydroxy
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001142 Aromatic-L-Amino-Acid Decarboxylases An enzyme group with broad specificity. The enzymes decarboxylate a range of aromatic amino acids including dihydroxyphenylalanine (DOPA DECARBOXYLASE); TRYPTOPHAN; and HYDROXYTRYPTOPHAN. Amino Acid Decarboxylases, Aromatic,Aromatic Amino Acid Decarboxylase,Aromatic Amino Acid Decarboxylases,5-HTPase,5-Hydroxytryptophan Decarboxylase,Aromatic-L-Amino-Acid Decarboxylase,Hydroxytryptophan Decarboxylase,Tryptophan Decarboxylase,5 HTPase,5 Hydroxytryptophan Decarboxylase,Aromatic L Amino Acid Decarboxylase,Aromatic L Amino Acid Decarboxylases,Decarboxylase, 5-Hydroxytryptophan,Decarboxylase, Aromatic-L-Amino-Acid,Decarboxylase, Hydroxytryptophan,Decarboxylase, Tryptophan,Decarboxylases, Aromatic-L-Amino-Acid
D012701 Serotonin A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator. 5-HT,5-Hydroxytryptamine,3-(2-Aminoethyl)-1H-indol-5-ol,Enteramine,Hippophaine,Hydroxytryptamine,5 Hydroxytryptamine
D051379 Mice The common name for the genus Mus. Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus

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