Francini F, Gagliardino J J
CENEXA-Centro de Endocrinología Experimental y Aplicada (UNLP-CONICET), Facultad de Ciencias Médicas UNLP, Argentina.
Comp Biochem Physiol B Biochem Mol Biol. 1998 Sep;121(1):111-5. doi: 10.1016/s0305-0491(98)10132-3.
Pancreas pieces of Bufo arenarum were incubated with several sugars at basal and stimulatory concentrations, and with inhibitors of their metabolism, measuring the insulin released by radioimmunoassay. Glucose, mannose, fructose, glyceraldehyde and dihydroxyacetone all at 8 mM, significantly enhanced the release of insulin elicited by basal concentrations of these carbohydrates (2 mM). The nonmetabolizable sugars galactose and 2-deoxyglucose failed to enhance insulin secretion. N-Acetyl-glucosamine at 8 mM did not significantly affect the release of insulin. D-Glucose, but not L-glucose, at 8 mM stimulated insulin secretion above baseline (2 mM glucose). At 8 mM, the D-glucose alpha-anomer significantly increased insulin release, while this effect was not observed using the beta-anomer. Insulin release elicited by 2 mM of the alpha-anomer was significantly higher than that triggered by the beta-anomer. Iodoacetate (5 mM), and dinitrophenol (0.3 mM) exerted an inhibitory effect upon glucose-induced insulin secretion. The effect of these carbohydrates and metabolic inhibitors--tested for the first time in amphibians--was similar to that described in the mammalian pancreas, thus suggesting that such compounds play an important role in the metabolic control of insulin secretion in amphibians.
将沙蟾的胰腺组织块与几种处于基础浓度和刺激浓度的糖类一起孵育，并与它们代谢的抑制剂一起孵育，通过放射免疫测定法测量释放的胰岛素。葡萄糖、甘露糖、果糖、甘油醛和二羟基丙酮在8 mM时，均显著增强了这些碳水化合物基础浓度（2 mM）引发的胰岛素释放。不可代谢的糖类半乳糖和2-脱氧葡萄糖未能增强胰岛素分泌。8 mM的N-乙酰葡糖胺对胰岛素释放没有显著影响。8 mM的D-葡萄糖而非L-葡萄糖刺激胰岛素分泌高于基线水平（2 mM葡萄糖）。8 mM时，D-葡萄糖α-异头物显著增加胰岛素释放，而使用β-异头物时未观察到这种效应。2 mM的α-异头物引发的胰岛素释放显著高于β-异头物引发的胰岛素释放。碘乙酸盐（5 mM）和二硝基苯酚（0.3 mM）对葡萄糖诱导的胰岛素分泌产生抑制作用。这些碳水化合物和代谢抑制剂的作用——首次在两栖动物中进行测试——与在哺乳动物胰腺中描述的作用相似，因此表明这些化合物在两栖动物胰岛素分泌的代谢控制中起重要作用。
