The variation of serum glucose, hepatic glycogen content and expression of glucose metabolism-related genes in hybrid grouper (female Epinephelus fuscoguttatus × male Epinephelus lanceolatus) in response to intraperitoneal insulin infusion

• Published in: Fisheries science 2018-07, Vol.84 (4), p.641-647
• Main Authors: Li, Songlin, Li, Ziqiang, Sang, Chunyan, Zhang, Jiacan, Chen, Naisong
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Body mass; Catalysis; Fish; Fish & Wildlife Biology & Management; Food Science; Freshwater & Marine Ecology; Fructose; Gene expression; Genes; Glucokinase; Gluconeogenesis; Glucose; Glucose metabolism; Glucose transporter; Glucose-6-phosphatase; Glycogen; Glycogen phosphorylase; Glycogen synthase; Glycolysis; Injection; Insulin; Kinases; Life Sciences; Liver; Marine fishes; Metabolism; Original Article; Phosphatase; Phosphofructokinase; Phosphorylase; Pyruvate kinase; Pyruvic acid; Serum; Transcription
• ISSN: 0919-9268; 1444-2906
• DOI: 10.1007/s12562-018-1208-3

The present study was conducted to investigate the effects of insulin on serum glucose, hepatic glycogen content and expression of glucose metabolism-related genes in hybrid grouper. Triplicate groups of five fish were sampled at the 0, 1, 3, 6, 12, 24 or 48-h time point post-bovine insulin (5 μg 100/g fish body mass) injection. A significant decrease of serum glucose content was observed along with the depletion of hepatic glycogen content at the 12-h time point following insulin injection. Hepatic gene expression analysis revealed that the infusion of insulin significantly increased the expression of glucose transporters (GLUTs), GLUT1b and GLUT2. The transcription of gluconeogenesis-related genes, fructose-1,6-bisphosphatase 1a and glucose-6-phosphatase a catalytic subunit tandem duplicate 2, was significantly decreased at the 12-h time point, while the expression of glycolysis-related genes, phosphofructokinase liver b and pyruvate kinase L/R, was significantly up-regulated at the 24-h time point post-insulin injection. Meanwhile, the expression of glucokinase significantly increased immediately following insulin administration. The expression of glycogen synthase liver type significantly decreased at the 12-h time point, while the expression of glycogen phosphorylase liver type was significantly elevated at the 24-h time point following insulin injection. These results suggested that insulin could affect glucose metabolism through regulating gluconeogenesis, glycolysis and glycogen metabolism at the transcriptional level.