Abstract
The responses of enzyme activities and metabolic intermediate concentrations to a short-time exercise and following resting were examined in the muscle and hepatopancreas of carp Cyprinus carpio. A 20 s exercise significantly increased phosphofructokinase (PFK) activity together with fructose-6-phosphate (F6P), AMP, and ADP concentrations and decreased phosphocreatine (PCr) and glycogen contents in the muscle. The exercise also increased activities of glucose-6-phosphatase (G6Pase), fructose-1, 6-bisphosphatase (FBPase), and alanine aminotransferase in the hepatopancreas as well as concentrations of glucose, lactate, and free amino acid in the serum. A 45 min resting period after the exercise tended to recover many enzyme activities and body component concentrations to the pre-exercise values, but activities of hepatopancreatic G6Pase and FBPase remained high during this period. These results suggest that the exercise enhanced in vivo glycolysis through the activation of PFK in muscle to supply ATP for the energy source. In addition, a higher gluconeogenesis in the hepatopancreas seems to make a contribution to restore muscle components such as PCr and glycogen during exercise and the resting period, showing an interdependence of carbohydrate metabolism between muscle and hepatopancreas.
