title: Deiodinase type 1 activity is expressed in the prostate of pubescent rats and is modulated by thyroid hormones, prolactin and sex hormones.
abstract: The aim of this study was to characterize the type of 5'-deiodinase activity in the prostate of pubescent rats (7-8 weeks), to establish its distribution in the lobes (ventral, dorsolateral, and anterior), and to analyze its modulation by prolactin (PRL), testosterone, dihydrotestosterone (DHT), and 17beta-estradiol (E(2)). Our results showed that the enzymatic activity was highly susceptible to inhibition by 6-n-propyl-2-thiouracil and gold thioglucose, its preferential substrate was reverse tri-iodothyronine (rT(3)), it exhibited a low dithiothreitol requirement (5 mM), and the apparent K(m) and V(max) values for substrate (rT(3)) were approximately 0.25 microM and 9.0 pmol liberated/mg protein per hour, respectively. All these characteristics indicate the preferential expression of type 1 deiodinase (D1), which was corroborated by demonstrating the presence of D1 mRNA in prostate. D1 activity was detected in all lobes and was most abundant in the dorsolateral. Although we detected type 2 deiodinase (D2) mRNA expression, the D2 activity was almost undetectable. D1 activity was enhanced in animals with hyperthyroidism and hyperprolactinemia, in intact animals treated with finasteride (inhibitor of local DHT production), and in castrated animals with E(2) replacement. In contrast, activity diminished in castrated animals with testosterone replacement. Our results suggest that thyroid hormones, PRL, and E(2) exert a positive modulation on D1 activity, while testosterone and DHT exhibit an inhibitory effect. D1 activity may be associated with prostate maturation and/or function.
authors.affiliation: Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, UNAM-Juriquilla, Km 15, Carretera Qro-SLP, Juriquilla, Querétaro 76230, México.
authors.forename: Brenda
authors.initials: B
authors.lastname: Anguiano
authors.forename: Alejandra
authors.initials: A
authors.lastname: López
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Delgado
authors.forename: Carlos
authors.initials: C
authors.lastname: Romero
authors.forename: Carmen
authors.initials: C
authors.lastname: Aceves
mesh_terms: D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D018120:Finasteride / Q000494:pharmacology; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D007453:Iodide Peroxidase / Q000032:analysis* / Q000235:genetics; D008297:Male; D009919:Orchiectomy; D010902:Pituitary Gland / Q000637:transplantation; D011388:Prolactin / Q000494:pharmacology*; D011467:Prostate / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012741:Sexual Maturation / Q000502:physiology*; D013268:Stimulation, Chemical; D013739:Testosterone / Q000494:pharmacology; D013963:Thyroid Hormones / Q000494:pharmacology*; D013974:Thyroxine / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D012739:Gonadal Steroid Hormones; D012333:RNA, Messenger; D013963:Thyroid Hormones; D013739:Testosterone; D004958:Estradiol; D018120:Finasteride; D011388:Prolactin; C109812:iodothyronine deiodinase type I; D007453:Iodide Peroxidase; D013974:Thyroxine