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

Autor(es)

Ribeiro, Rosane A. ^[1] ; Vanzela, Emerielle C. ^[1] ; Oliveira, Camila A. M. ^[1] ; Bonfleur, Maria L. ^[1] ; Boschero, Antonio C. ^[1] ; Carneiro, Everardo M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas UNICAMP, Inst Biol, Dept Anat Biol Celular & Fisiol & Biofis, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: BRITISH JOURNAL OF NUTRITION; v. 104, n. 8, p. 1148-1155, OCT 2010.
• Citações Web of Science: 39

Resumo

Taurine (TAU) supplementation increases insulin secretion in response to high glucose concentrations in rodent islets. This effect is probably due to an increase in Ca(2+) 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 mu M-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 Ca(2+) mobilisation and PLC(beta 2) protein expression. The Ca(2+) 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 PKA alpha protein. This protein may play a role in cation accumulation, since the amount of Ca(2+) 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 Ca(2+), and these effects seem to involve the activation of both PLC-inositol-1,4,5-trisphosphate and cAMP-PKA pathways. (AU)

• Processo FAPESP: 08/53811-8 - Caracterização morfofuncional de ilhotas pancreáticas de camundongos submetidos à restrição protéica ou à dieta hiperlipídica e suplementados com taurina
• Beneficiário: Everardo Magalhães Carneiro
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 05/59707-0 - Secreção e sinalização de insulina e movimento de cálcio em ilhotas pancreáticas de camundongos suplementados com taurina
• Beneficiário: Rosane Aparecida Ribeiro
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 07/50365-4 - Estudo dos mecanismos de destruição das células beta pancreáticas durante a instalação do Diabetes Mellitus (DM2): busca de estratégias para a inibição desse processo bem como para a recuperação da massa insular em diferentes modelos animais
• Beneficiário: Antonio Carlos Boschiero
• Linha de fomento: Auxílio à Pesquisa - Temático