Regulation of the uterine expression of messenger ribonucleic acids encoding the oestrogen receptor and IGF-I peptides in the pig uterus.
The acute effects of oestradiol-17 beta on the expression of the oestrogen receptor (ER) and insulin-like growth factor I (IGF-I) in the endometrium of ovariectomized pigs were examined. The steroid receptor level was assayed by hormone binding techniques and specific mRNAs analyzed by solution hybridization using 35S-labelled RNA probes complementary to the ligand-binding domain of the ER receptor gene and a 160 bp PanI-Pvul fragment of the IGF-I gene. One hour after a single injection of oestradiol (1 micrograms/kg BW), the nuclear oestrogen receptor (ERn) mean level was increased 3-fold whereas the ER mRNA content had not changed significantly. After 3 hours the ERn mean concentration was still high; the mean ER mRNA level had decreased by 15% and the mean IGF-I mRNA had increased 3-fold above that in the samples collected prior to treatment from these ovariectomized animals. Six hours after the injection the ERn content had returned to the basal level and stayed there during the following six hours. The ER mRNA concentration continued to decline, reached its lowest value after six hours and had increased slightly by twelve hours. The IGF-I mRNA level increased steadily during the course of the experiment. At twelve hours after the injection it had increased 3-fold. From these data we conclude that in the pig uterus oestradiol down-regulates its own receptor and acts as a potent stimulator of endometrial growth by inducing IGF-I expression.
Sahlin
L
L
Dept. of Reproductive Endocrinology, Karolinska Hospital, Stockholm, Sweden.
Rodriguez-Martinez
H
H
Stanchev
P
P
Dalin
A M
AM
Norstedt
G
G
Eriksson
H
H
D000818:Animals; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D011960:Receptors, Estrogen / Q000235:genetics*; D013552:Swine / Q000378:metabolism*; D014599:Uterus / Q000187:drug effects / Q000378:metabolism*
D012333:RNA, Messenger; D011960:Receptors, Estrogen; D004958:Estradiol; D007334:Insulin-Like Growth Factor I