Selenoprotein gene expression in thyroid and pituitary of young pigs is not affected by dietary selenium deficiency or excess.
Expression and function of selenoproteins in endocrine tissues remain unclear, largely due to limited sample availability. Pigs have a greater metabolic similarity and tissue size than rodents as a model of humans for that purpose. We conducted 2 experiments: 1) we cloned 5 novel porcine selenoprotein genes; and 2) we compared the effects of dietary selenium (Se) on mRNA levels of 12 selenoproteins, activities of 4 antioxidant enzymes, and Se concentrations in testis, thyroid, and pituitary with those in liver of pigs. In Experiment 1, porcine Gpx2, Sephs2, Sep15, Sepn1, and Sepp1 were cloned and demonstrated 84-94% of coding sequence homology to human genes. In Experiment 2, weanling male pigs (n = 30) were fed a Se-deficient (0.02 mg Se/kg) diet added with 0, 0.3, or 3.0 mg Se/kg as Se-enriched yeast for 8 wk. Although dietary Se resulted in dose-dependent increases (P < 0.05) in Se concentrations and GPX activities in all 4 tissues, it did not affect the mRNA levels of any selenoprotein gene in thyroid or pituitary. Testis mRNA levels of Txnrd1 and Sep15 were decreased (P < 0.05) by increasing dietary Se from 0.3 to 3.0 mg/kg. Comparatively, expressions of Gpx2, Gpx4, Dio3, and Sep15 were high in pituitary and Dio1, Sepp1, Sephs2, and Gpx1 were high in liver. In conclusion, the mRNA abundances of the 12 selenoprotein genes in thyroid and pituitary of young pigs were resistant to dietary Se deficiency or excess.
International Center of Future Agriculture for Human Health, Sichuan Agricultural University, Chengdu, Sichuan 611134, China.
Ji-Chang
JC
Zhou
Hua
H
Zhao
Jun-Gang
JG
Li
Xin-Jie
XJ
Xia
Kang-Ning
KN
Wang
Ya-Jun
YJ
Zhang
Yan
Y
Liu
Ying
Y
Zhao
Xin Gen
XG
Lei
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D003001:Cloning, Molecular; D004032:Diet / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D012643:Selenium / Q000008:administration & dosage* / Q000172:deficiency* / Q000494:pharmacology; D051140:Selenoproteins / Q000235:genetics / Q000378:metabolism*; D013552:Swine / Q000378:metabolism*; D013737:Testis / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism*
D051140:Selenoproteins; D012643:Selenium