용존산소(DO)의 급격한 증가에 순응된 꺽지(Coreoperca herzi)와 모래무지(Pseudogobio esocinus) 조직내 젖산탈수소효소(EC 1.1.1.27, lactate dehydrogenase, LDH)의 대사와 $C_4$ 동위효소를 확인하였다. DO 18 ppm에 갑작스럽게 순응시 꺽지 LDH활성은 뇌와 간조직에서 각각 $35-39\%$ 변화되었고, 다른 조직에서는 $20\%$이내로 변화가 적었다. 골격근조직은 LDH $A_4$ 동위효소가 증가되고 하부단위체 C를 포함하는 동위효소는 감소되었다. 심장조직은 $B_4$ 동위효소가 조금 증가되었다. 신장조직도 $B_4$가 증가하고 눈 조직은 eye-specific $C_4$와 C hybrid가 감소되어 조절되었다. DO 증가에 갑작스럽게 순응한 모래무지 간조직에서 LDH 활성은 30분에서 급격하게 $150\%$이상 크게 증가되었고, 다른 조직에서는 $70\%$ 이상 변화되었다. 그리고 골격근조직은 $A_4$ 동위효소가 증가하고 다른 조직들에서는 $B_4$가 증가되었으며 특히 간 조직의 대사는 liver-specific $C_4$가 증가하고 $A_4$ 는 감소되어 조절되었다. 그러나 꺽지 눈 조직의 대사는 LDH 활성이 감소하고 eye-specific $C_4$ 동위효소가 감소되어 조절되었다. 따라서 DO증가에 순응시 모래무지는 꺽지에 비해 LDH 활성이 크게 증가되었고 동위효소의 변화정도도 크게 나타났으며, eye-spe-cific $C_4$와 liver-specific $C_4$ 동위효소는 lactate oxidase로서 대사를 조절하였다. 그러므로 환경변화에 순응하여 나타나는 대사는 종이 이전에 어떤 서식조건에 적응되었는가에 따라 다른 것으로 사료된다.
The metabolism of lactate dehydrogenase (EC 1.1.1.27, LDH) and $C_4$ isozyme were studied in tissues of Coreoperca herzi and Pseudogobio esocinus acclimated to rapid increase of dissolved oxygen (DO). In C. herzi the LDH activity was changed $35-39\%$ in brain and liver tissues, and within $20\%$ in other tissues. The $B_4$ isozyme was increased and isozyme containing subunit C was decreased in muscle tissue. The $B_4$ isozyme was increased in heart and kidney. In P. esocinus, the LDH activity in liver tissues was largely increased to $150\%$ for 30 minute and $70\%$ in other tissues. The $A_4$ isozyme was increased in muscle and $B_4$ isozyme was increased in other tissues. Especially, the metabolism of liver tissue in P. esocinus was regulated by increasing liver-specific $C_4$ and decreasing $A_4$ isozyme. But the metabolism of eye tissue in C. herzi was regulated by decreasing LDH activity and eye-specific $C_4$ isozyme. The LDH activity and LDH isozyme in P. esocinus were largely increased than C. herzi acclimated to rapid increase of DO. And eye-specific $C_4$ and liver-specific $C_4$ isozymes played role as lactate oxidase. Therefore, the response of species acclimated to rapid increase of DO seems to be variable, perhaps due to prior exposure to environmental conditions.
