Effects of glucose injection on serum indices and gene expression of carbohydrate metabolic enzymes in large yellow croaker (Larimichthys crocea)

This experiment was conducted to evaluate the effects of intraperitoneal glucose injection on serum indices, hepatic glycolysis and gluconeogenic key enzyme expression levels of intraperitoneal glucose injection of large yellow croaker (Larimichthys crocea). Fish n=270, mean weight=(100±5) g were randomly assigned to three groups, a control group that was injected with sterile 0.9% normal saline, the low dosage group that was injected with glucose (300 mg/kg wet weight, LG) and the high dosage group with glucose (1500 mg/kg wet weight, HG). The results showed that ①the plasma glucose level reached a peak at 3 h after both dose glucose injections, and returned to base level at the time of 24 h after injection of low dosage glucose, and it was still higher than base level after 24 h after high dosage glucose relatively. ②The trend of relative expression of HK gene after both dose glucose injections was increased first, then decreased, and reached the peak at 9 h. The relative expression of GK gene trend was to rise first and then remained unchanged and finally fell after both dose glucose injections, and it reached the peak at 9 h, but it was decreased at 4 h after high dosage glucose. The relative expression of PFK gene presented the trend of first increasing and then decreasing, and it reached the highest at 9 h after high dosage glucose. ③The trend of relative expression of PEPCK gene decreased first and then increased, and it reached the minimum at 2 h after high dosage glucose. ④It was significantly higher at 6 h than at any other time point, after high dosage glucose. These results indicate that the plasma glucose level of large yellow croaker increased, and maintained for a long time. The absence of inhibition in the expression of the gluconeogenic enzyme of G6Pase, FBPase concurrent with increased postprandia expression of GK led to postprandial hyperglycaemia in large yellow croaker.