Changes of Respiratory Chain Enzyme Activities in Growing Rat Muscle Mitochondria

爲確立肌肉粒線體呼吸鏈酵素活性是否出生時即達成熟狀態亦或出生後才逐漸發展到成人的水準，由於從政黨幼兒取得肌肉有其執行上之困難，故我們以白鼠(Wistar rat)爲實驗的對象，共有六群，每群20隻，年齡別爲三週、四週、五週、六週、十週和二十六週；我們選擇m. extensor digitorum longus爲實驗的肌肉，並挑選Rotenone sensitive NADH-cytochrome c reductase，succinate-cytochrome c reductase和cytochrome c oxidase等三種粒線體呼吸鏈酵素爲探討之對象，因這三種酵素的缺乏是引起人類肌肉粒線體病變最常見的生化異常。結果：Rotenone sensitive NADH-cytochrome c reductase的活性在出生後不久（至少是十週以內）是相當的低，與另外兩種酵素比較起來，其開始發展的時間也比較晚。Succinate-cytochrome c redutase的活性在出生後不久（三週）即可達成年者之70%，其成熟發展曲線爲三種酵素中最爲平坦者。Cytochrome c oxidase在出生後不久（三週）僅約成年者之25%，四到六週大時約爲80%，十週大時則可高達92%，其成熟發展曲線爲早期快速成熟。由此實驗結果可知，幼小白鼠肌肉粒線體呼吸鏈酵素活性會隨年齡成長而有差異。在過去的文獻報告中，有關人類的肌肉粒體病變的生化異常，其所謂的正常值往往包括由非粒線體病變所取得之肌肉所測得之酵素值，這包括成年人和幼童；如果人類幼童的肌肉粒線體呼吸鏈酵素也會隨年齡的成長而有所差異，則我們更應特別小心來解釋由幼小病童肌肉所測得之酵素值，以免做出錯誤之診斷。此研究仍屬動物實驗之階段，故雖然人類幼兒肌肉之來源有限，我們仍然需急切了解人類幼兒時期之肌肉粒線體呼吸鏈酵素活性之發展情形以做爲正確診斷之參攷。

關鍵字

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並列摘要

The activities of three mitochondrial respiratory chain enzymes, namely rotenone sensitive NADH-cytochrome c reductase (NCCR), succinate-cytochrome c reductase (SCCR), and cytochrome c oxidase (CCO) in the extensor digitorum longus muscle were determined in Wistar rats, twenty each, at 3, 4, 5, 6, 10 and 26 weeks of age. The activity of NCCR was extremely low from birth up to 10 weeks of age. The activity of SCCR was stable at 64% to 72% during the first 6 weeks of life and increased to 78% of the adult level at 10 weeks of age. The CCO activity was only 52% of the adult level at 3 weeks of age, increased to 78% to 86% during the next 3 weeks and reached 92% at 10 weeks of age which was not statistically different from the adult level. We conclude that the activities of these 3 respiratory chain enzymes, in muscle mitochondna in rats, were low during development and reached the adult levels at various ages. Before the normal values of these enzyme activities can be established in human pediatric population, age-matched control should be used as the reference valus for evaluation of mitochondrial myopathy.

並列關鍵字

NADH-cytochrome c reductase ； succinate-cytochrome c reductase ； cytochrome c oxidase ； rat muscle

國際替代計量

Changes of Respiratory Chain Enzyme Activities in Growing Rat Muscle Mitochondria

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