Developmental regulation of placental insulin-like growth factor (IGF)-II and IGF-binding protein-1 and -2 messenger RNA expression during primate pregnancy.
The present study was conducted to determine the developmental expression of placental insulin-like growth factor (IGF)-II, IGF-binding protein (IGFBP)-1 and -2, and IGF-II receptor mRNA expression during baboon pregnancy and whether estrogen, the levels of which increase with advancing pregnancy, regulates placental trophoblast IGF-II mRNA expression. Levels of the IGF-II 6.1-kilobase (kb) and 4.9-kb mRNA transcripts determined by Northern blot analysis progressively increased three- to fourfold in placental syncytiotrophoblast and whole-villous tissue between early (Day 60), mid (Day 100), and late (Day 170) baboon gestation (term = 184 days). In contrast, syncytiotrophoblast IGFBP-1 and -2 mRNA levels decreased, and IGF-II receptor mRNA expression remained relatively constant, with advancing baboon pregnancy. Placental cytotrophoblast IGF-II mRNA levels determined by competitive reverse transcription-polymerase chain reaction on Day 54 of gestation were increased (P < 0.05) almost twofold at 18 h after acute administration of estradiol to baboons, whereas long-term estrogen treatment had no effect. We propose that these changes in trophoblast IGF expression would provide a mechanism for enhancing net bioavailability and bioreactivity of IGF-II locally to promote the growth and development of the placenta and, consequently, of the fetus during primate pregnancy.
Zollers
W G
WG
Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
Babischkin
J S
JS
Pepe
G J
GJ
Albrecht
E D
ED
D000818:Animals; D015152:Blotting, Northern; D002824:Chorionic Villi / Q000737:chemistry; D004958:Estradiol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D005260:Female; D020567:Fetal Weight; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D005865:Gestational Age; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000235:genetics*; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics*; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D009929:Organ Size; D010215:Papio; D010920:Placenta / Q000033:anatomy & histology / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis*; D017527:Receptor, IGF Type 2 / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014327:Trophoblasts / Q000737:chemistry
D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D012333:RNA, Messenger; D017527:Receptor, IGF Type 2; D004958:Estradiol; D007335:Insulin-Like Growth Factor II