Ontogeny of the generation of diiodothyronines (3,3'-T2 and 3',5'-T2) from triiodothyronines in the liver and kidney during the fetal life of the pig.
The present study was conducted to obtain information on the generation of diiodothyronines from triiodothyronines (3,3'-T2 from T3, and rT3, and 3',5'-T2 from rT3) as a result of the activity of the tissue monodeiodinase enzymes (MD) in the liver and kidney of pig fetuses and their mothers between 32 and 113 days of gestation. T3-5-MD activity in the fetal kidney during the gestational period was stable and higher than in the liver and in the maternal kidney. In contrast, T3-5-MD activity of the liver was 3-4 times lower in fetal than in maternal tissue in the first half of pregnancy, and in the second half of pregnancy 3,3'-T2 production from T3 in the maternal liver was equal to, or lower than, that in the fetal liver. The activity of MD deiodinating rT3 (3,3'-T2 and 3',5'-T2 generation) increased significantly in fetal liver and kidney in the last 2-3 weeks of pregnancy and was higher than in maternal tissues. In both tissues examined the inner ring deiodinating activity (IRD) was 5-10 times lower as compared to the outer ring (ORD).
Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, Department of Developmental and Experimental Endocrinology, Poznań, Poland.
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Krysin
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Brzezińska-Slebodzińska
D000818:Animals; D004104:Diiodothyronines / Q000378:metabolism*; D005314:Embryonic and Fetal Development; D005260:Female; D005865:Gestational Age; D007668:Kidney / Q000196:embryology / Q000378:metabolism*; D008099:Liver / Q000196:embryology / Q000378:metabolism*; D011247:Pregnancy; D013552:Swine; D014284:Triiodothyronine / Q000378:metabolism*; D014285:Triiodothyronine, Reverse / Q000378:metabolism
D004104:Diiodothyronines; D014284:Triiodothyronine; C030103:3,5-diiodothyronine; D014285:Triiodothyronine, Reverse; C030102:3',5'-diiodothyronine