TY - JOUR
T1 - Antioxidant enzymatic activity in embryos and placenta of rats chronically exposed to hypoxia and hyperoxia
AU - Mover, Haya
AU - Ar, Amos
PY - 1997/6
Y1 - 1997/6
N2 - Embryos exhibit lower enzymatic antioxidant activity (EAOA) than adults, in accordance with the low in utero oxygen concentration. We asked whether external oxygen stress can modulate embryonic EAOA and what the placenta role is as a mediator between embryos and external milieu. Pregnant rats were exposed to hyperoxia (90% O2) or hypoxia (10% O2) during 8 days in the second or third trimester. Activities of catalase (CAT), superoxide dismutase and glutathione peroxidase (GPx) were measured in the term embryonic brain, lung and heart and liver; 2-week-old whole embryonic sac and placenta. In term 'hyperoxic' embryos, only CAT increased by 30% in heart and lungs and liver. In the placenta, GPx increased by 31%. In term 'hypoxic' embryos, only CAT activity decreased by 64%, 25% and 29% in brain, liver, and placenta. In 2-week-old 'hyperoxic' embryos CAT activity increased by 85% and GPx by 45% in the embryonic sac. In the placenta, GPx increased by 55%. The limited embryonic EAOA response is possibly due to maternal physiological buffering of oxygen supply. Placental EAOA is similar to other embryonic organs. It may protect the placenta proper, thus ensuring normal embryonic development.
AB - Embryos exhibit lower enzymatic antioxidant activity (EAOA) than adults, in accordance with the low in utero oxygen concentration. We asked whether external oxygen stress can modulate embryonic EAOA and what the placenta role is as a mediator between embryos and external milieu. Pregnant rats were exposed to hyperoxia (90% O2) or hypoxia (10% O2) during 8 days in the second or third trimester. Activities of catalase (CAT), superoxide dismutase and glutathione peroxidase (GPx) were measured in the term embryonic brain, lung and heart and liver; 2-week-old whole embryonic sac and placenta. In term 'hyperoxic' embryos, only CAT increased by 30% in heart and lungs and liver. In the placenta, GPx increased by 31%. In term 'hypoxic' embryos, only CAT activity decreased by 64%, 25% and 29% in brain, liver, and placenta. In 2-week-old 'hyperoxic' embryos CAT activity increased by 85% and GPx by 45% in the embryonic sac. In the placenta, GPx increased by 55%. The limited embryonic EAOA response is possibly due to maternal physiological buffering of oxygen supply. Placental EAOA is similar to other embryonic organs. It may protect the placenta proper, thus ensuring normal embryonic development.
KW - Catalase
KW - Embryos
KW - Glutathione peroxidase
KW - Hyperoxia
KW - Hypoxia
KW - Placenta
KW - Rat
KW - Superoxide dismutase
UR - http://www.scopus.com/inward/record.url?scp=0030836777&partnerID=8YFLogxK
U2 - 10.1016/S0742-8413(97)00062-5
DO - 10.1016/S0742-8413(97)00062-5
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AN - SCOPUS:0030836777
SN - 0742-8413
VL - 117
SP - 151
EP - 157
JO - Comparative Biochemistry and Physiology - C Pharmacology Toxicology and Endocrinology
JF - Comparative Biochemistry and Physiology - C Pharmacology Toxicology and Endocrinology
IS - 2
ER -