Modulação colinergica da secreção de insulina em ilhotas de ratos alimentados com dieta hipoproteica

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

We studied the effects of carbamy1choline (CCh) and Phorbol 12-Myristate 13 Acetate (PMA), in insulin secretion of isolated Largerhans islets of male Wistar rats maintained with normal protein diet (17% of protein =NP) or low protein diet (6% of protein =LP). Islets isolated by collagenase digestion of pancreata, were incubated (lh) in Krebs medium with 8.3 mM or 16.7 mM of glucose (G), with or without CCh and PMA. The insulin content of media was available by radioimunoassay. Concentrations of CCh (O, l-I 000 j..lM) increased insulin secretion in both groups. Stimulation with CCh shifted the LP dose-response curve to the right (LP Ecso = 4.64:tO,98 and NP Ecso = 2.15 0,70) (p<0,05). When the islets were stimulated with PMA (20011M) the increased in insulin secretion was higher Ín NP islets (3.04 fold for 8.3 mM ofG and 1.50 fold for 16.7 mM of G) (p<0.05). Immunocitoquemical showed a decrease in PKCa content in LP islets and Western blot analysis revealed that PKCa and PLCf31 expression in LP isolated rat islets, after 2.5 h of incubation in 8.3 mM glucose media, were lower than NP (p<0.05) and RTPCR showed a decrease in rnRNA levels to PKCa (p<0.05). Low protein intake is associated with a lowered PKCa and PLCf31 expression in Langerhans islets. This alteration may be one factor involved in reduced insulin secretion by LP animals isolated islets, when stimulated with CCh and PMA in presence of glucose

ASSUNTO(S)

insulina pancreas desnutrição

ACESSO AO ARTIGO

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