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Effects of ATP concentration and hypoxic exposure on RNA and protein synthesis activity in isolated mitochondria from rat brain

Liu Junze, Gao Wenxiang, Cai Mingchun, Cao Lifei, Sun Bingyong

Department of Pathophysiology,College of High Altitude Military Medicine,Third Military Medical University.Chongqing 400038

Abstract

The results showed that there was a 40% reduction in RNA synthesis and a 60% inhibition in protein synthesis in isolated mitochondria in vitro in acute hypoxia exposure compared to control. But in chronic hypoxic exposure, the inhibition of both RNA synthesis and protein synthesis was alleviated, being 72% and 76% of the normoxic control, respectively. Furthermore, the effect of ATP concentration in medium on mitochondrial RNA and protein synthesis in vitro showed two phases. The mitochondrial RNA and protein synthesis were inhibited when ATP concentration was either above or below 1 mmol/L in the incubation medium. These results indicate that hypoxia exposure affects the expression of mtDNA at both transcription and translation levels. It also suggests that the improvement of mitochondrial semi-automation during chronic hypoxic exposure may be at least one of the cellular mechanisms of body adaptation to hypoxia. The regulation of ATP in mitochondrial RNA and protein synthesis is therefore an economic and effective mode of regulation.

Key words: Mitochondria;Hypoxia;ATP;Mitochondrial RNA synthesis;Mitochondrial protein synthesis

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Citing This Article：

Liu Junze, Gao Wenxiang, Cai Mingchun, Cao Lifei, Sun Bingyong. Effects of ATP concentration and hypoxic exposure on RNA and protein synthesis activity in isolated mitochondria from rat brain. Acta Physiol Sin 2002; 54 (6): (in Chinese with English abstract).