Blood samples collected from the caudal vessels of anesthetized (MS-222, 100mg/l) carp Cyprinus carpio (boby weight: about 500g, May, water temperature: 20°C) with 10ml plastic syringe tipped with a 20-gauge stainless steel needle were placed in three plastic tubes, and cen-trifuged after being kept for 0.5, 3 and 24 h at 4C, respectively.
Serum uric acid level and Acid P (EC 3.1.3.2) activity increased with the lapse of time. The mean values of the former were 126.4% (3 h-value) and 149.6% (24 h-value) of 0.5 h-value (100%). Those of the latter were 252.9% (3 h) and 309.8% (24 h). In contrast, potassium level decreased to 75.1% (3 h) and 50.5% (24 h). GPT (EC 2.6.1.2) activity decreased to 82.5% (3 h) and 25.8% (24 h), too. Glucose level decreased slightly, but inorganic P, magnesium and calcium levels increased slightly. Levels of sodium and chloride and GOT (EC 2.6.1.1) activity did not change. Activities of LDH (EC 1.1.1.27) and CK (EC 2.7.3.2) did not show a tendency to vary. The cause of these variations was discussed in terms of the change during the storage of serum, the mobilization between serum and blood cells, and the blood coagulation.
Even if the sample is kept at 4C, it is desirable to obtain the serum as fast as possible after blood sampling.