苯并［a］芘对黑鲷肝脏GST活性的影响及其与肝脏代谢酶和胆汁代谢产物之间的变化关系

为探讨苯并a]芘(Ba]P)暴露对鱼类的影响并筛选特异、敏感的生物标志物,研究了Ba]P对黑鲷(Sparus macrocephalus)肝脏谷胱甘肽-S-转移酶(GST)活性的影响,并分析了肝脏7-乙氧基异吩唑酮-脱乙基酶(EROD)、GST活性与胆汁中Ba]P典型代谢产物3-羟基-苯并a]芘(3-OHBa]P)3者之间及与Ba]P之间的剂量、时间-效应关系.结果显示:在Ba]P(0.5、1.0、2.0和5.0μg·L-1)暴露期间,肝脏GST活性随暴露时间总体呈"钟"形的变化趋势,在第2d时达到峰值;在第12h、1d和2d时,GST活性与Ba]P暴露浓度呈显著正相关(R12h=0.966(p<0.05)、R1d=0.953(p<0.05)、R2d=0.824(p<0.05)).与前期研究结果对比分析发现,Ba]P(0.5、1.0、2.0和5.0μg·L-1)暴露7d时,胆汁中3-OHBa]P浓度与Ba]P暴露浓度呈显著的剂量-效应关系(R=0.943,p<0.05);黑鲷肝脏GST、EROD活性与3-OHBa]P的对数浓度均呈显著正相关(RGST=0.740(p<0.05)、REROD=0.839(p<0.05));2.0μg·L-1Ba]P暴露后,黑鲷肝脏EROD、GST活性与3-OHBa]P随暴露时间的变化趋势基本相同,但并不完全一致.鱼类肝脏EROD、GST与胆汁中Ba]P代谢产物3者之间的变化关系较为复杂,暴露浓度和时间是影响其变化的重要因素,肝脏GST和EROD活性比胆汁中代谢产物更易受其影响,在Ba]P的环境监测中代谢产物可能是一种更为可行的生物标志物.

Effects of Benzo[a]pyrene Exposure on Hepatic GST Activity in Black Porgy(Sparus macrocephalus)and Variation Relationships with Hepatic Metabolic Enzymes and Biliary Metabolites

Effects of benzoapyrene(BaP)exposure on the activity of glutathione S -transferase(GST)in black porgy (Sparus macrocephalus)liver was studied. The dose and time response of two enzymes (7-ethoxyresorufin O -deethylase (EROD) and GST)involved in BaP metabolism and the amounts of BaP metabolites excreted into the bile were investigated. Results showed that the time -response trend on of induction of hepatic GST of black porgy was bell -shaped with a plateau at BaP exposure for 2 days. A significant dose-related increase of the GST activity in liver was observed at the exposure time of 12h, 1d and 2d (R12h=0.966, p<0.05; R1d=0.9529, p<0.05; R2d=0.824, p<0.05). Compared with our former study, the induction of hepatic EROD, GST activities and biliary 3-OH BaP of black porgy were significantly induced by BaP (0.5, 1.0, 2.0 and 5.0μg·L-1)after exposure for 7 days and a significant dose -response relationship between 3-OH BaP and BaP was observed(R=0.943, p<0.05). After exposed to 2.0μg·L-1 BaP, similar variation trends of hepatic EROD, GST activities and biliary 3-OH BaP had been observed in black porgy, but those variations were not consistency with the time change completely. Those results demonstrated that the variation between hepatic metabolic enzymes and biliary metabolites were very complex. The exposure concentrations and exposure time were the most important factors which influence the variations of metabolic enzymes and metabolites.