Phenylhydrazine으로 유발된 빈혈에 대한 방어기전으로서의 Superoxide Dismutase의 역할 = The Role of the Superoxide Dismutase as Protecting Mechanism Of Rabbit Erythrocyte Against Phenylhydrazine-induced Anemia

다국어 초록 (Multilingual Abstract)

Cytotoxic superoxide radical(O_2^-) is a common intermediate of oxygen reduction in the respiring cells and therefore these cells should be protected against the cytotoxic effects of superoxide radicals. Superoxide dismutase(EC 1.15.1.1) is an enzyme that makes a defence against the toxicity of superoxide radical. At present time, three types of superoxide dismutase(SOD), copper and zinc-containing, manganese containing and iron containing enzyme, have been isolated from both eukaryotic and prokaryotic cells. In this study, we have carried out an experiment to establish the general patterns of cynthesis and degradation of SOD in rabbit that was induced hemolytic anemia by phenylhydrazine and normal, sequential measurements of activity of SOD in the cytosolic and mitochondrial fraction of normal and phenylhydrazine treated rabbits were conducted. The kinetic study of rabbit red blood cell(RBC) during cytodifferentiation provides a unique system which permitted a comparison of the isozymes' turnover rates in vivo. Also, in order to observe the role of SOD as protecting mechanism against O_2^- radicals in this experimental system, these data were treated according to kinetic method of the Kopelovich. The activity of SOD was measured by the method of McCord and Fridovich.
The experimental results are summarized as follows;
1. The activity of cytosolic and mitochondrial SOD of normal rabbit RBC was 42 units and 1.5 units per ml RBC, respectively.
2. The reticulocyte counts of normal rabbit RBC was approximately 2.5% and administration of phenylhydrazine resulted in rapid and profound reticulocytosis, i.e., about 63.5% on day 6 and essentially 100% on day 7.
3. The hematocrit of normal rabbit blood was 36%, but after treatment of phenylhydrazine, it was decreased to 20.2% in the value on 4th day.
4. In the phenylhydrazine treated rabbit RBC, activity of cytosolic SOD was maximal on day 5, about 108 units per ml RBC which is about 2.6 fold higheh than the normal value. At induction period, rate constants of synthesis(K_s) and degradation(K_d) were 3.9312 and 0.0364, respectively, the half life was 19.04hrs. K_s and K_d following recovery from phenylhydrazine treatment were 0.5781 and 0.0141, respectively, and the half life was 49.0hrs.
5. The activity of mitochondrial SOD was maximal on day 5, about 5.5 fold higher than the normal value. During induction period, rate constants of synthesis and degradation were 0.1640 and 0.0200, respectively, and the half lief was 34.65 hrs K_s and K_d following recovery from phenylhydrazine treatment were 0.0384 and 0.0256, respectively, and the half life was 27.1 hrs.