Nippon Suisan Gakkaishi 65 (5), 896-900 (1999)

Response of Hepatopancreatic Enzyme Activities and Metabolic Intermediate Concentrations to Bovine Insulin and Glucose Administration in Carp Cyprinus carpio

Tsuyoshi Sugita,*2 Sadao Shimeno,*2 Hidetsuyo Hosokawa,*2 and Toshiro Masumoto*2

The responses of hepatopancreatic enzyme activities and metabolic intermediate concentrations to bovine insulin and glucose administration were examined in carp Cyprinus carpio. An intraperitoneal insulin injection significantly decreased the concentrations of serum glucose and amino acids in the fish. The insulin injection increased activities of hepatopancreatic phosphofructokinase (PFK) and G6PDH as well as concentrations of hepatopancreatic F6P, AMP, and ADP, while it decreased activities of FBPase and G6Pase. These results suggest that the insulin injection enhanced in vivo glycolysis through the activation of PFK. It was also suggested that PFK was activated by the conformation change of PFK as well as changes in concentrations of metabolic intermediates in hepatopancreas rather than the induction of PFK.

On the other hand, the oral glucose administration rapidly increased serum glucose concentration, but the enzyme activities and metabolic intermediate concentrations were not much affected at 2 hours after glucose administration. However, they were shifted to a pattern similar to that of insulin injection at 6 hours after glucose administration. This may indicate that glucose administration also activated hepatopancreatic glycolysis through an increased secretion of insulin with a short time lag.


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