Eilertson C D, O'Connor P K, Sheridan M A
Department of Zoology, North Dakota State University, Fargo 58105.
Gen Comp Endocrinol. 1991 May;82(2):192-6. doi: 10.1016/0016-6480(91)90183-7.
The effects of somatostatin-14 (SS-14) and salmon somatostatin-25 (sSS-25) on hepatic glycogenolysis were studied by incubating rainbow trout liver pieces in vitro. Glycogen content in untreated liver pieces cultured for 3 and 5 hr was 28.6 +/- 7.6 mg/g fresh wt. and 21.5 +/- 6.6 U, respectively. Treatment of liver pieces with either SS-14 or sSS-25 resulted in significant glycogen depletion; sSS-25 appeared more potent in this regard. Equimolar concentrations (10(-8) M) of SS-14 or sSS-25 reduced glycogen content to 10.6 +/- 1.6 and 2.6 +/- 2.2 U, respectively, in liver pieces incubated for 3 hr. Alterations in liver glycogen content were reflected in glucose release into medium. Basal release of glucose into culture medium over the course of a 3-hr incubation was 20 +/- 5.6 mumol/g dry wt. Both SS-14 and sSS-25 stimulated a rapid increase (500 and 600%, respectively) in glucose release during the first 0.5 hr of incubation. After 3 hr, SS-14 and sSS-25 stimulated glucose release over basal levels to 116 +/- 9.3 and 153 +/- 16 U, respectively. Both SS-14 and sSS-25 stimulated glucose release in a dose-dependent manner; ED50 for both peptides was ca. 5 X 10(-8) M. These results indicate that both SS-14 and sSS-25 directly mediate hepatic glycogenolysis in rainbow trout.
通过体外孵育虹鳟鱼肝组织块，研究了生长抑素 -14（SS -14）和鲑鱼生长抑素 -25（sSS -25）对肝糖原分解的影响。未处理的肝组织块培养3小时和5小时后的糖原含量分别为28.6±7.6毫克/克鲜重和21.5±6.6单位。用SS -14或sSS -25处理肝组织块均导致糖原显著减少；在这方面，sSS -25似乎更有效。在孵育3小时的肝组织块中，等摩尔浓度（10⁻⁸M）的SS -14或sSS -25分别将糖原含量降至10.6±1.6单位和2.6±2.2单位。肝糖原含量的变化反映在葡萄糖释放到培养基中。在3小时的孵育过程中，葡萄糖向培养基中的基础释放量为20±5.6微摩尔/克干重。在孵育的最初0.5小时内，SS -14和sSS -25均刺激葡萄糖释放迅速增加（分别为500%和600%）。3小时后，SS -14和sSS -25将葡萄糖释放量刺激至高于基础水平，分别达到116±9.3单位和153±16单位。SS -14和sSS -25均以剂量依赖方式刺激葡萄糖释放；两种肽的半数有效剂量（ED50）约为5×10⁻⁸M。这些结果表明，SS -14和sSS -25均直接介导虹鳟鱼肝糖原分解。
