Different experimental conditions which regulate type II 5'-deiodinase mRNA in rat Harderian gland.
In the present study, we describe the modifications in the expression of type II 5'deiodinase activity (5'D) in Xenopus laevis oocytes by injection of polyadenylated (poly A) mRNA from hypothyroid rat Harderian gland. The time-course study showed that the expression of the enzyme was dependent on time. Thus, enzyme activity was observed in oocytes 6 and 12 hours after the injection with poly A mRNA, reaching a maximal value at 24 hours. The activity was partially inhibited by 6-n-propyl-thiouracil, completely inhibited by iopanoic acid and exhibited a higher affinity for the T4 (Km=1.5 nM) than rT3 (Km=20 nM). The expression of the enzyme was modified in different experimental conditions: (a) exhibited diurnal variations with maximal peak values at night, (b) was inhibited by light at night and, (c) was activated by isoproterenol. On the other hand, we have also identified, for the first time, the size of mRNA capable of inducing 5'D in rats.
Garcia-Macias
J F
JF
Department of Medical Biochemistry and Molecular Biology, The University of Seville School of Medicine and Virgen Macarena Hospital, Spain.
Molinero
P
P
Rubio
A
A
Guerrero
J M
JM
Osuna
C
C
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D002940:Circadian Rhythm; D003624:Darkness; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006243:Harderian Gland / Q000201:enzymology*; D007037:Hypothyroidism; D007453:Iodide Peroxidase / Q000235:genetics* / Q000378:metabolism; D007480:Iopanoic Acid / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D008027:Light; D008297:Male; D008845:Microinjections; D009865:Oocytes; D011441:Propylthiouracil / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013974:Thyroxine / Q000378:metabolism; D014285:Triiodothyronine, Reverse / Q000378:metabolism; D014982:Xenopus laevis; D000097564:Iodothyronine Deiodinase Type II
D000318:Adrenergic beta-Agonists; D007453:Iodide Peroxidase; D007480:Iopanoic Acid; D007545:Isoproterenol; D011441:Propylthiouracil; D012333:RNA, Messenger; D013974:Thyroxine; D014285:Triiodothyronine, Reverse; D000097564:Iodothyronine Deiodinase Type II