This paper aims to evaluate the individual and joint toxicities of cadmium sulfate （CdSO4） and α-naphthoflavone （ANF） in zebrafish embryos. As a result, CdSO4 caused both lethal and sub-lethal effects, such as 24...This paper aims to evaluate the individual and joint toxicities of cadmium sulfate （CdSO4） and α-naphthoflavone （ANF） in zebrafish embryos. As a result, CdSO4 caused both lethal and sub-lethal effects, such as 24 h post-fertilization （hpf） death and 72 hpf delayed hatching. However, ANF only caused sub-lethal effects, including 48 hpf cardiac edema and 72 hpf delayed hatching. Taking 24 hpf death and 48 hpf cardiac edema as endpoints, the toxicities of CdSO4 and ANF were significantly enhanced by each other. Consistently, both CdSO4 and ANF caused significant oxidative stress, including decreases in the reduced glutathione （GSH） level, inhibition of superoxide dis- mutase （SOD） activity, as well as increases in malondialdehyde （MDA） content in zebrafish embryos, but these mixtures produced much more significant alterations on the biomarkers. Co-treatment of CdSO4 and ANF significantly down-regulated the mRNA level of multidrug resistance-associated protein （mrp） 1 and cytochrome P450 （cyp） la, which constituted the protective mechanisms for zebraflsh embryos to chemical toxins. In conclusion, co-treatment of CdSO4 and ANF exhibited a much more severe damage in zebraflsh embryos than individual treatment. Meanwhile, production of oxidative stress and altered expression of mrpl and cypla could be important components of such joint toxicity.展开更多
AIM To study the influence of inducers BNFand PB on the stereoselective metabolism ofpropranolol in rat hepatic microsomes.METHODS Phase Ⅰ metabolism of propranololwas studied by using the microsomes induced byBNF an...AIM To study the influence of inducers BNFand PB on the stereoselective metabolism ofpropranolol in rat hepatic microsomes.METHODS Phase Ⅰ metabolism of propranololwas studied by using the microsomes induced byBNF and PB and the non-induced microsome asthe control.The enzymatic kinetic parameters ofpropranolol enantiomers were calculated byregression analysis of Lineweaver-Burk plots.Propranolol concentrations were assayed byHPLC.RESULTS A RP-HPLC method was developed todetermine propranolol concentration in rathepatic microsomes.The linearity equations forR（+）-propranolol and S（-）-propranolol wereA=705.7C+311.2C（R = 0.9987）and A= 697.2C+311.4C（R = 0.9970）respectively.Recoveriesof each enantiomer were 98.9%,99.5%,101.0%at 60 μmol/L,120 μmol/L,240 μmol/Lrespectively.At the concentration level of120 μmol/L,propranolol enantiomers weremetabolized at different rates in differentmicrosomes.The concentration ratio R（+）/S（-）of control and PB induced microsomesincreased with time,whereas that of microsomeinduced by BNF decreased.The assayed enzymeparameters were:1.Km.Control group:R（+）30+<sub>8</sub>,S（-）18+<sub>5</sub>;BNFgroup:R（+）34+3,S（-）39±7;PB group:R（+）38±17,S（-）36±10.2.Vmax.Control group:R（+）1.5+0.2,S（-）2.9±0.3;BNF group:R（+）3.8±0.3,S（-）3.3±0.5;PB group:R（+）0.07±0.03,S（-）1.94±0.07.3.Clint.Control group:R（+）60±3,S（-）170±30;BNF group:R（+）111.0±1,S（-）84± 5;PBgroup:R（+）2.0±2,S（-）56.0±1.Theenzyme.parameters compared with unpaired ttests showed that no stereoselectivity wasobserved in enzymatic affinity of threemicrosomes to enantiomers and their catalyticabilities were quite different and hadstereoselectivities.Compared with the control,microsome induced by BNF enhanced enzymeactivity to propranolol R（+）-enantiomer,andmicrosome induced by PB showed less enzymeactivity to propranolol S（-）-enantiomer whichremains the same stereoselectivities as that ofthe control.CONCLUSION Enzyme activity centers of themicrosome were changed in composition andregioselectivity after the induction of BNF andPB,and the stereoselectivities of propranololcytochrome P450 metabolism in rat hepaticmicrosomes were likely due to thestereoselectivities of the catalyzing function inenzyme.CYP1A subfamily induced by BNFexhibited pronounced contribution to propranololmetabolism with stereoselectivity to R（+）-enantiomer.CYP2B subfamily induced by PBexhibited moderate contribution to propranololmetabolism,but still had the stereoselectivity ofS（-）-enantiomer.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 21307154）
文摘This paper aims to evaluate the individual and joint toxicities of cadmium sulfate （CdSO4） and α-naphthoflavone （ANF） in zebrafish embryos. As a result, CdSO4 caused both lethal and sub-lethal effects, such as 24 h post-fertilization （hpf） death and 72 hpf delayed hatching. However, ANF only caused sub-lethal effects, including 48 hpf cardiac edema and 72 hpf delayed hatching. Taking 24 hpf death and 48 hpf cardiac edema as endpoints, the toxicities of CdSO4 and ANF were significantly enhanced by each other. Consistently, both CdSO4 and ANF caused significant oxidative stress, including decreases in the reduced glutathione （GSH） level, inhibition of superoxide dis- mutase （SOD） activity, as well as increases in malondialdehyde （MDA） content in zebrafish embryos, but these mixtures produced much more significant alterations on the biomarkers. Co-treatment of CdSO4 and ANF significantly down-regulated the mRNA level of multidrug resistance-associated protein （mrp） 1 and cytochrome P450 （cyp） la, which constituted the protective mechanisms for zebraflsh embryos to chemical toxins. In conclusion, co-treatment of CdSO4 and ANF exhibited a much more severe damage in zebraflsh embryos than individual treatment. Meanwhile, production of oxidative stress and altered expression of mrpl and cypla could be important components of such joint toxicity.
基金the National Natural Science Foundation of China,No.39370805.
文摘AIM To study the influence of inducers BNFand PB on the stereoselective metabolism ofpropranolol in rat hepatic microsomes.METHODS Phase Ⅰ metabolism of propranololwas studied by using the microsomes induced byBNF and PB and the non-induced microsome asthe control.The enzymatic kinetic parameters ofpropranolol enantiomers were calculated byregression analysis of Lineweaver-Burk plots.Propranolol concentrations were assayed byHPLC.RESULTS A RP-HPLC method was developed todetermine propranolol concentration in rathepatic microsomes.The linearity equations forR（+）-propranolol and S（-）-propranolol wereA=705.7C+311.2C（R = 0.9987）and A= 697.2C+311.4C（R = 0.9970）respectively.Recoveriesof each enantiomer were 98.9%,99.5%,101.0%at 60 μmol/L,120 μmol/L,240 μmol/Lrespectively.At the concentration level of120 μmol/L,propranolol enantiomers weremetabolized at different rates in differentmicrosomes.The concentration ratio R（+）/S（-）of control and PB induced microsomesincreased with time,whereas that of microsomeinduced by BNF decreased.The assayed enzymeparameters were:1.Km.Control group:R（+）30+<sub>8</sub>,S（-）18+<sub>5</sub>;BNFgroup:R（+）34+3,S（-）39±7;PB group:R（+）38±17,S（-）36±10.2.Vmax.Control group:R（+）1.5+0.2,S（-）2.9±0.3;BNF group:R（+）3.8±0.3,S（-）3.3±0.5;PB group:R（+）0.07±0.03,S（-）1.94±0.07.3.Clint.Control group:R（+）60±3,S（-）170±30;BNF group:R（+）111.0±1,S（-）84± 5;PBgroup:R（+）2.0±2,S（-）56.0±1.Theenzyme.parameters compared with unpaired ttests showed that no stereoselectivity wasobserved in enzymatic affinity of threemicrosomes to enantiomers and their catalyticabilities were quite different and hadstereoselectivities.Compared with the control,microsome induced by BNF enhanced enzymeactivity to propranolol R（+）-enantiomer,andmicrosome induced by PB showed less enzymeactivity to propranolol S（-）-enantiomer whichremains the same stereoselectivities as that ofthe control.CONCLUSION Enzyme activity centers of themicrosome were changed in composition andregioselectivity after the induction of BNF andPB,and the stereoselectivities of propranololcytochrome P450 metabolism in rat hepaticmicrosomes were likely due to thestereoselectivities of the catalyzing function inenzyme.CYP1A subfamily induced by BNFexhibited pronounced contribution to propranololmetabolism with stereoselectivity to R（+）-enantiomer.CYP2B subfamily induced by PBexhibited moderate contribution to propranololmetabolism,but still had the stereoselectivity ofS（-）-enantiomer.
