Taurine supplementation: involvement of cholinergic/phospholipase C and protein kinase A pathways in potentiation of insulin secretion and Ca2+ handling in mouse pancreatic islets

• Published in: British journal of nutrition Vol. 104; no. 8; pp. 1148 - 1155
• Main Authors: Ribeiro, Rosane A., Vanzela, Emerielle C., Oliveira, Camila A. M., Bonfleur, Maria L., Boschero, Antonio C., Carneiro, Everardo M.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 28.10.2010
• Subjects: 1-Methyl-3-isobutylxanthine - pharmacology; animal models; Animals; anions; biochemical pathways; Biological and medical sciences; Ca2+ handling; calcium; Calcium - metabolism; Carbachol - pharmacology; Cells, Cultured; Colforsin - pharmacology; Cyclic AMP-Dependent Protein Kinases - genetics; Cyclic AMP-Dependent Protein Kinases - metabolism; Cytoplasm; Dietary Supplements; Drinking water; enzyme inhibitors; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Glucose; human nutrition; Insulin - metabolism; Insulin Secretion; islets of Langerhans; Islets of Langerhans - metabolism; Kinases; Mice; nutrient uptake; Nutritional Endocrinology; Pancreas; Phorbol Esters - pharmacology; Phospholipase C; Phospholipase C beta - genetics; Phospholipase C beta - metabolism; Protein kinase A; protein kinase C; Protein Kinase C-alpha - genetics; Protein Kinase C-alpha - metabolism; protein synthesis; Rodents; taurine; Taurine - administration & dosage; Taurine - pharmacology; Taurine supplementation; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Protein kinase A; Taurine supplementation; Ca2+ handling; Insulin secretion; Phospholipase C; Potentiation; Taurine; Pancreatic hormone; Protein kinase C; Calcium; Enzyme; Secretion; Transferases; Non-specific serine/threonine protein kinase; Rodentia; Langerhans islet; Insulin; Vertebrata; Mammalia; Mouse; Animal; Supplementation; Ca; Endocrine pancreas; Handling
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114510001820

Taurine (TAU) supplementation increases insulin secretion in response to high glucose concentrations in rodent islets. This effect is probably due to an increase in Ca2+ handling by the islet cells. Here, we investigated the possible involvement of the cholinergic/phospholipase C (PLC) and protein kinase (PK) A pathways in this process. Adult mice were fed with 2 % TAU in drinking water for 30 d. The mice were killed and pancreatic islets isolated by the collagenase method. Islets from TAU-supplemented mice showed higher insulin secretion in the presence of 8·3 mm-glucose, 100 μm-carbachol (Cch) and 1 mm-3-isobutyl-1-methyl-xanthine (IBMX), respectively. The increase in insulin secretion in response to Cch in TAU islets was accompanied by a higher intracellular Ca2+ mobilisation and PLCβ2 protein expression. The Ca2+ uptake was higher in TAU islets in the presence of 8·3 mm-glucose, but similar when the islets were challenged by glucose plus IBMX. TAU islets also showed an increase in the expression of PKAα protein. This protein may play a role in cation accumulation, since the amount of Ca2+ in these islets was significantly reduced by the PKA inhibitors: N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline sulfonamide (H89) and PK inhibitor-(6–22)-amide (PKI). In conclusion, TAU supplementation increases insulin secretion in response to glucose, favouring both influx and internal mobilisation of Ca2+, and these effects seem to involve the activation of both PLC–inositol-1,4,5-trisphosphate and cAMP–PKA pathways.