[Protective effect of low concentration endothelin-1 on the reactive oxygen-induced inhibition of pulmonary surfactant lipid synthesis].
The effects of endothelin-1 (ET-1) at low concentration (1-100 pmol/L) on the reactive oxygen-induced inhibition of both pulmonary surfactant (PS) lipid synthesis and the activity of CTP: phosphorylcholine cytidylyltransferase (CCT), a rate-limiting enzyme in biosynthesis of phosphoatidylcholine (PC), were studied in cultured lung explants without serum. The xanthine-xanthine oxidase superoxide anion generating system decreased (3)H-choline incorporation into PC in a dose-dependent manner in cultured lung explants. ET-1 reduced both the reactive oxygen-induced decrease in (3)H-choline incorporation and the increase in malondialdehyde (MDA) content of lung tissues, but did not change the levels of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and the total antioxidant capability in the lung explants. ET-1 enhanced microsomal CCT activity of the lung tissues, while it decreased cytosolic CCT activity of lung tissues. ET-1 also prevented the inhibitive effect of reactive oxygen on microsomal CCT activity in the lung explants. These results suggest that ET-1 at low concentration can protect the microsomal CCT activity and reduce the inhibition of PS lipid synthesis induced by oxidant lung injury. The protective mechanism of ET-1 is not relative to the pulmonary endogenous antioxidant defense system.
Luo
Zi-Qiang
ZQ
Department of Physiology, Xiangya Medical College, Central Southern University, Changsha 410078. ziqiangluo@hotmail.com
Feng
Dan-Dan
DD
Zhou
Fu-Wen
FW
Zhang
Chang-Qing
CQ
Qin
Xiao-Qun
XQ
Sun
Xiu-Hong
XH
D000818:Animals; D019916:Choline-Phosphate Cytidylyltransferase / Q000378:metabolism; D019332:Endothelin-1 / Q000008:administration & dosage* / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D010743:Phospholipids / Q000096:biosynthesis*; D011663:Pulmonary Surfactants / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000633:toxicity*
D019332:Endothelin-1; D010743:Phospholipids; D011663:Pulmonary Surfactants; D017382:Reactive Oxygen Species; D019916:Choline-Phosphate Cytidylyltransferase