Putrescine Uptake in Rat Type II Pneumocytes Correlates with γ-Glutamyltransferase Activity
- 作者：van Klaveren ; Rob J. ; Hoet ; Peter H. M. ; Demedts ; Maurits ; Nemery ; Benoit
- 关键词：Polyamines ; Hyperoxia ; l-Buthionine-[S ; R]-sulfoximine ; Glutathione ; Paraquat
- 刊名：The International Journal of Biochemistry and Cell Biology
- 出版年：1997
- 期刊代码：127_13572725
- 类别：med
- 出版时间：April, 1997
- 卷：29
- 期：4
- 页码：605-609
- 文件大小：405 K
摘要
γ-Glutamyltransferase (γGT) is a key enzyme in glutathione metabolism and it is thought also to play a role in the uptake of polyamines such as putrescine. The aim of our study was to investigate if changes in γGT activity would alter total putrescine uptake [Pup(tot)], as well as more specific uptake via the γGT pathway [Pup(γGT)]. Forty-eight hours after their isolation, rat type II cells were exposed to 30, 60 or 125 μM l-buthionine-[SR]-sulfoximine (BSO) for 3 hr; 200 or 800 μM tertiary-butylhydroperoxide (t-BOOH) for 40 min; 10, 100 or 1000 μM paraquat (PQ) for 1 hr; and 60 or 85%O2 for 48 hr. The γGT activity, Pup(tot) and Pup(γGT) (assessed by inhibiting γGT) were measured immediately after the exposure to hyperoxia, or 24 hr after treatment with BSO, t-BOOH or PQ. From previous studies, it is known that these experimental conditions increased (BSO, 200 μM t-BOOH) or decreased (800 μM t-BOOH, PQ, hyperoxia) γGT activity. There was a strong correlation between the changes in γGT activity and the changes in Pup(γGT) (r = 0.81, p < 0.001). These findings support the hypothesis that γGT partly regulates the uptake of putrescine, one of the polyamines required for cell growth and differentiation.