关键词: 斑马鱼, 胰岛素, 血糖, 葡萄糖转运蛋白

Abstract: Zebrafish (Danio rerio) shows persistent hyperglycemia under glucose loading status. Compared with control group which was only injected intraperitoneally with sterilized deionized water, the expression of insulin gene was significantly up-regulated in glucose group which was only injected intraperitoneally with glucose, while there were no significant differences in plasma insulin level and the expression of hepato-pancreas glucose transporters genes. The result indicated that insufficient insulin secretion and delayed glucose transport of zebrafish would result in persistent hyperglycemia. In order to observe the effect of exogenous insulin on blood glucose and its transport in vivo, we designed low (1.25 IU/kg), medium (12.5 IU/kg) and high (125 IU/kg) concentrations of insulin, and co-injected zebrafish with glucose (0.1 g/mL), and then observed the changes of blood glucose. The low dose of exogenous insulin was found to be the optimal injection concentration, which could effectively promote the reduction of blood glucose in zebrafish, and could directly reflect the change of blood glucose after glucose loading. Also, the research showed that the changes of blood glucose were not affected by gender. At the optimal injection concentration of insulin, insulin group (co-injection of glucose with insulin) could significantly reduce the time of blood glucose recovering to normal level when compared with glucose group. And further analysis showed that plasma insulin level increased and the expression of glucose transporters genes were significantly up-regulated, however, the expression of insulin gene was significantly inhibited. Taken together, the above results indicated that insufficient insulin secretion and delayed glucose transport were the causes of persistent hyperglycemia in zebrafish, and exogenous insulin could promote the decrease of blood glucose, whereas it could feedback suppress the expression of insulin gene in hepatopancreas.

Key words: zebrafish (Danio rerio), insulin, blood glucose, GLUTs