Eilertson C D, Sheridan M A
Department of Zoology, North Dakota State University, Fargo 58105, USA.
Am J Physiol. 1995 Nov;269(5 Pt 2):R1017-23. doi: 10.1152/ajpregu.1995.269.5.R1017.
Previous work suggested that teleost fish possess two somatostatin (SS) genes. Regulation of differential secretion of SS gene I (SS-25) and SS gene II products (SS-14) by nutrients was studied using rainbow trout. Hemi-islets were cultured in medium containing different concentrations of glucose and arginine. SS-14 and insulin were determined by radioimmunoassay; SS-25 was determined by a novel enzyme-linked immunosorbent assay. Glucose stimulated SS-25 release in a concentration-related manner, with 10 mM being the most effective concentration; at higher (25 mM) glucose, release decreased. Insulin levels in the medium also were found to be more elevated from islets incubated in 10 mM glucose than those incubated in 25 mM glucose. Maximum SS-14 release was observed at lower (1-5 mM) glucose concentrations. Arginine stimulated SS release so that maximum release of both SS forms occurred at the lowest glucose concentrations (1 mM). A concentration-related effect of arginine was observed on SS-25 release. The results of this study indicate that glucose and arginine regulate secretion of both pancreatic SS gene I and gene II products from rainbow trout islets, suggesting that two different pancreatic SS interact in nutrient homeostasis in this species.
先前的研究表明，硬骨鱼拥有两个生长抑素（SS）基因。利用虹鳟鱼研究了营养物质对SS基因I（SS - 25）和SS基因II产物（SS - 14）分泌差异的调节作用。将半胰岛培养在含有不同浓度葡萄糖和精氨酸的培养基中。通过放射免疫分析法测定SS - 14和胰岛素；通过一种新型酶联免疫吸附测定法测定SS - 25。葡萄糖以浓度相关的方式刺激SS - 25的释放，10 mM为最有效浓度；在较高（25 mM）葡萄糖浓度下，释放量下降。还发现，在10 mM葡萄糖中培养的胰岛培养基中的胰岛素水平比在25 mM葡萄糖中培养的胰岛更高。在较低（1 - 5 mM）葡萄糖浓度下观察到最大的SS - 14释放量。精氨酸刺激SS的释放，使得两种SS形式的最大释放量都出现在最低葡萄糖浓度（1 mM）时。观察到精氨酸对SS - 25释放具有浓度相关效应。本研究结果表明，葡萄糖和精氨酸调节虹鳟鱼胰岛中胰腺SS基因I和基因II产物的分泌，这表明两种不同的胰腺SS在该物种的营养稳态中相互作用。
