title: Regulation of insulin-like growth factor-I and thioredoxin expression by estradiol in the reproductive tract of the prepubertal female lamb.
abstract: Estradiol (E(2)) has been shown to be an important uterine growth promoting molecule in the ovariectomized (ovx) rat, which increases the mRNA levels of insulin-like growth factor-I (IGF-I) and the redox enzyme thioredoxin. The aim of this study was to explore the role of E(2) in the regulation of IGF-I and thioredoxin in the reproductive tract of the prepubertal female lamb. Twenty 3-month-old lambs were treated with i.m. injections of E(2) at 24 h intervals. The animals were sacrificed 12 or 24 h after the last injection, and 72 h was the longest treatment period. The mRNA levels of thioredoxin and IGF-I were determined by a solution hybridization technique. There was a 5-fold increase in the cervical IGF-I mRNA level 12 h after the first E(2) injection. The uterine IGF-I mRNA level was doubled after 12 h and this increase was maintained during the rest of the experimental period. The IGF-I mRNA level in the oviducts was more than doubled 12 and 24 h after the E(2) injection, then the level decreased towards the initial level. The thioredoxin mRNA level in the cervix was increased 4-fold after 24 h, whereas no significant effect was seen in the uterus. The thioredoxin mRNA level in the oviduct was more than doubled 12 and 24 h after the first E(2) injection. Thus, estradiol regulates the expression of IGF-I and thioredoxin in the reproductive tract of prepubertal lambs.
authors.affiliation: Department of Woman and Child Health, Division for Reproductive Endocrinology, Karolinska Hospital, L5:01, S-171 76 Stockholm, Sweden. lena.sahlin@kbh.ki.se
authors.forename: L
authors.initials: L
authors.lastname: Sahlin
authors.forename: A
authors.initials: A
authors.lastname: Meikle
authors.forename: C
authors.initials: C
authors.lastname: Tasende
authors.forename: M
authors.initials: M
authors.lastname: Lindberg
authors.forename: B
authors.initials: B
authors.lastname: Masironi
authors.forename: H
authors.initials: H
authors.lastname: Eriksson
mesh_terms: D000818:Animals; D004958:Estradiol / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D005836:Genitalia, Female / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012741:Sexual Maturation; D012756:Sheep; D013879:Thioredoxins / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D004958:Estradiol; D013879:Thioredoxins; D007334:Insulin-Like Growth Factor I