Glucose to lerance test was performed with allogynogenetic silver crucian carp( Carassius auralus gibelio a @ Cyprinus carpio ` ) , whose initial weight was 46 ? 5g, after the f ish had fasted for 4 weeks. Blood and liver were collected before and 1, 2, 3, 4, 5, 6, 8, 10, 14, 18 and 24h af ter being administered orally with 167mg glucose per 100g body weight . The results showed that the plasma glucose level increased sharply during 3h and reached a peak at 3h after oral administration, and then decreased slowly. Plasma triglyceride peaked at 1h after administration and thereafter started to decrease, which re-increased after 8h. During the first 2h after glucose administration the liver glycogen content decreased significantly, and thereafter increased to a peak value, which was reached 6h after glucose administration. Different doses of glucose were administered to the same species , which had fasted for 4 weeks and whose initial average body weight was 164 ? 12g, to investigate the change of plasma glucose level and liver glycogen content. The results showed that with the dose of glucose increasing , the plasma glucose level increased. However, the liver glycogen content decreased with the increasing of glucose dose. These results indicated that there is native difference in secretion of insulin between allogynogenetic silver crucian carp and mammals.