Developmental Regulation of Placental Insulin-Like Growth Factor (IGF)-II and IGF-Binding Protein-1 and -2 Messenger RNA Expression During Primate Pregnancy

• Published in: Biology of reproduction 2001-10, Vol.65 (4), p.1208-1214
• Main Authors: ZOLLERS, William G, BABISCHKIN, Jeffery S, PEPE, Gerald J, ALBRECHT, Eugene D
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blotting, Northern; Chorionic Villi - chemistry; Embryology: invertebrates and vertebrates. Teratology; Estradiol - administration & dosage; Estradiol - blood; Estradiol - pharmacology; Female; Fetal membranes; Fetal Weight; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - drug effects; General aspects. Development. Fetal membranes; Gestational Age; Insulin-Like Growth Factor Binding Protein 1 - genetics; Insulin-Like Growth Factor Binding Protein 2 - genetics; Insulin-Like Growth Factor II - genetics; Organ Size; Papio; Placenta - anatomy & histology; Placenta - metabolism; Pregnancy; Receptor, IGF Type 2 - genetics; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - analysis; Trophoblasts - chemistry
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod65.4.1208

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.