Efeitos da glicose sobre a secreção de insulina, e fluxo do 45Ca e concentração citoplasmatica do Ca2+ em ilhotas de Langherns de ratos adultos, recem-isladas ou mantidas em cultura

AUTOR(ES)
DATA DE PUBLICAÇÃO

1991

RESUMO

The present study aimed at comparing the effects of glucose on ionic and secretoty events in freshly isolated and cultured rat pancreatic islets. For this pourpose islets from female adult fed Wistar rats were isolated by collagenase digestion. Part of these islets were cultured for 5 to 7 days in a mixture of BME basal medium and Dulbecco´s modified medium used in a 5/2 volumetric ratio, and supplemented with 10% newborn calf serum to yield a final concentration of glucose close to 10.5 mM. The culture medium was renewed every 48 hours. The islets were maintained at ?37 GRAUS?C in a 5% ?C??O IND. 2? atmosphere. Immediately before the experiments, the freshly isolated or cultured islets were washed twice with a bicarbonate-buffered solution. The methods used were: (a) Perifusion of freshly isolated or cultured islets to measure the ?CA SOB 45? outflow and insulin release; (b) Incubation of isolated cells, obtained from freshly or cultured islets, to measure the citosolic ?CA POT. 2+? concentration, using the Fura 2 as an intracellular ?CA POT. 2+? ?ndicator. The results show that: 1. The capacity of glucose to provoke insulin release was severely reduced in islets maintained in culture. 2. Wheter in freshly in isolated or cultured islets, glucose provoked a marked and sustained decrease in ?CA SOB. 45? out-flow from islets deprived of extracellular ?CA POT. 2+?. ...Note: The complete abstract is available with the full electronic digital thesis or dissertations

ASSUNTO(S)

insulina fisiologia

ACESSO AO ARTIGO

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