Borelli M I, Morano M I, Estivariz F E, Gagliardino J J
CENEXA-Centro de Endocrinologia Experimental y Aplicada (UNLP-CONICET), Facultad de Ciencias Médicas, UNLP, La Plata, Argentina.
Arch Int Physiol Biochim Biophys. 1994 Jan-Feb;102(1):17-20. doi: 10.3109/13813459408996100.
This work was performed to study the release of proopiomelanocortin (POMC)-derived peptides from isolated pancreatic islets and the effect of ACTH--a member of that peptide family--on insulin secretion. Islets were incubated with 3,3 and 16.6 mM glucose and insulin and ACTH-like products (ACTH-LP) were measured by radioimmunoassay. Glucose stimulated the simultaneous release of insulin and ACTH-LP, the ACTH-LP concentration being higher when assayed with an antibody reacting with the N-terminus of ACTH. However, the increment in this release in the presence of the higher glucose concentration was larger when measured with an antibody against the ACTH mid-portion. Thus, although the islets would release more of a smaller ACTH-LP, 16.6 mM glucose would selectively increase the release of peptides of larger molecular size. Islets incubated with different concentrations of synthetic ACTH (50-500 pg/ml) increased the release of insulin in a dose-dependent manner. These results suggest that the release of endogenous ACTH-LP could contribute to the paracrine regulation of insulin secretion.
本研究旨在探讨从分离的胰岛中释放阿片促黑素细胞皮质素原（POMC）衍生肽以及该肽家族成员促肾上腺皮质激素（ACTH）对胰岛素分泌的影响。将胰岛与3.3和16.6 mM葡萄糖一起孵育，并用放射免疫分析法测定胰岛素和ACTH样产物（ACTH-LP）。葡萄糖刺激胰岛素和ACTH-LP同时释放，当用与ACTH N端反应的抗体进行检测时，ACTH-LP浓度更高。然而，当用针对ACTH中部的抗体测量时，在较高葡萄糖浓度下这种释放的增加幅度更大。因此，尽管胰岛会释放更多较小的ACTH-LP，但16.6 mM葡萄糖会选择性地增加较大分子大小肽的释放。用不同浓度的合成ACTH（50-500 pg/ml）孵育的胰岛以剂量依赖的方式增加了胰岛素的释放。这些结果表明内源性ACTH-LP的释放可能有助于胰岛素分泌的旁分泌调节。
