Regulation of insulin-like growth factor-I and thioredoxin expression by estradiol in the reproductive tract of the prepubertal female lamb.
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.
Sahlin
L
L
Department of Woman and Child Health, Division for Reproductive Endocrinology, Karolinska Hospital, L5:01, S-171 76 Stockholm, Sweden. lena.sahlin@kbh.ki.se
Meikle
A
A
Tasende
C
C
Lindberg
M
M
Masironi
B
B
Eriksson
H
H
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*
D012333:RNA, Messenger; D004958:Estradiol; D013879:Thioredoxins; D007334:Insulin-Like Growth Factor I