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Войти в исследования Gastroenterology · 1996
Cell-generated nitric oxide inactivates rat hepatocyte mitochondria in vitro but reacts with hemoglobin in vivo.
Сравнительное исследованиеСтатьяПоддержка исследования: вне правительства СШАНазвание и аннотация: Перевод в очереди
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Fisch C, Robin M A, Letteron P, Fromenty B, Berson A, Renault S, Chachaty C, Pessayre D
Аннотация
BACKGROUND & AIMS: Nitric oxide forms inactive iron-nitrosyl complexes within hepatic mitochondria in vitro. However, when formed in vivo, NO might react instead with hemoglobin. The aim of this study was to compare the effects of cell-derived NO on rat hepatocyte mitochondria in vitro and in vivo.
METHODS: First, hepatocytes were cultured in vitro for 24 hours under a porous membrane supporting macrophages that were stimulated by endotoxin. Second, hepatic macrophage hyperplasia was induced in vivo by preadministration of killed Corynebacterium parvum; 7 days later, rats received endotoxin and were killed after 6 hours. Third, mitochondria were exposed to sodium nitroprusside in vitro, washed, mixed with blood, and recovered.
RESULTS: Iron-nitrosyl complexes and hepatocyte mitochondrial dysfunction were observed in the in vitro model and prevented by an NO synthase inhibitor. In the in vivo model, however, despite a 130-fold increase in plasma nitrate levels and formation of hemoglobin-NO complexes in blood, no iron-nitrosyl complex was detected in hepatic mitochondria, and hepatic mitochondrial function was not impaired. In the third model, mitochondria lost preformed iron-nitrosyl complexes when exposed to blood.
CONCLUSIONS: Although NO reacts with hepatocyte mitochondria in vitro, in vivo it reacts with sinusoidal hemoglobin without detectable impairment of hepatic mitochondrial function.
METHODS: First, hepatocytes were cultured in vitro for 24 hours under a porous membrane supporting macrophages that were stimulated by endotoxin. Second, hepatic macrophage hyperplasia was induced in vivo by preadministration of killed Corynebacterium parvum; 7 days later, rats received endotoxin and were killed after 6 hours. Third, mitochondria were exposed to sodium nitroprusside in vitro, washed, mixed with blood, and recovered.
RESULTS: Iron-nitrosyl complexes and hepatocyte mitochondrial dysfunction were observed in the in vitro model and prevented by an NO synthase inhibitor. In the in vivo model, however, despite a 130-fold increase in plasma nitrate levels and formation of hemoglobin-NO complexes in blood, no iron-nitrosyl complex was detected in hepatic mitochondria, and hepatic mitochondrial function was not impaired. In the third model, mitochondria lost preformed iron-nitrosyl complexes when exposed to blood.
CONCLUSIONS: Although NO reacts with hepatocyte mitochondria in vitro, in vivo it reacts with sinusoidal hemoglobin without detectable impairment of hepatic mitochondrial function.