정상토끼의 적혈구와 Phenylhydrazine을 주사한 후 경시적으로 채혈하여 lactate dehydrogenase isozyme의 활성도의 변동을 관찰하여 다음과 같은 결론을 얻었다. 1. 정상토끼 적혈구의 lactate dehydrogendse isozy-me의 활성도는 각각 98% 및 0.01%의 비율이다. 2. Phenylhydrazine 의 주사로 생성된 reticulocyte내의 이 효소 활성도는 주사 후 4일에 가장 높으며 약27unit며 약 5배의 증가를 보여준다. 3. Phenylhydrazine을 주사하여 생성된 reticulocyte내의 이 효소의 총 활성도의 증가 주로 Cytosol내의isozyme의 활성도가 약 5배 증가한데 기인하(K_s=0.0863;K_d=0.0031; t1/2=226hrs) Mitochondria에서 는 거의 변동이 없기 때문이다. 4. Phenylhydrazine 처치로부터 회복되었을 때의 적혈구의 lactate dehydrogenase isozyme들의 합성과 분해속도상수는 Mitochondrial isozyme; K_s=0.0029; K_d =0.0486; t1/2=14hrs이며 Cytosolic isozyme; K_s=0.1118; K_d=0.0233; t1/2=29hrs이다. 5. Reticulocyte 및 성숙 과정의 적혈구내의 lactatedehydrogenase isozyme의 생리적 역할에 관하여 고찰하였다.

A study on erythrocytes during cytodifferentiation was carried out of clarify the general pattern of synthesis and breakdawn of lactate dehydrogenase (L-lactate:NAD oxidoreductase, EC 1,1,1, 27) isozymes in phenylhydrazinetreated domestic rabbits. The rabbits were injected with phenylhydrazine on day 0,1 and 3 day and, at intervals, the blood samples were taken by cardiac puncture, and the activity of lactate dehydrogenase in erythrocytes was deter mined according to the method of Stolzenbach . The results obtained were as follows: 1. Total activity of lactate dehydrogenase in normal erythrocytes was about 4.9units, and the relative activity of cytosolic and mitochondrial lactate dehydrogenase isozymes was approximately 99% and 0.01%, respectively. 2. In phenylhydrazine-produced reticulocytosis, the total lactate dehydrogenase activity was maximal on 4th day, about 27 units, which is about five-fold higher than that of normal value. 3. The increase in total activity of lactate dehydrogenase during the induction of reticulocytosis was due primarily to 5.6-fold increase in the cytosolic isozyme (K_s=0.0863; K_d=0.0031; t 1/2=223hrs). The activity of mitochondrial isozyme was found to remain almost Unchanged. 4. The rates of constants following recovery from phenylhydrazine treatment were: K_s=0.0029 ; K_d=0.0486; t 1/2=14hrs, for mitochondrial isozyme and K_s= 0.1118; K_d=0.0233; t 1/2=29hrs for cytosolic isozyme. 5. The possible physiolocal role of lactate dehydrogenase isozymes in erythrocytes during reticulocytosis and maturation was discussed.