Developmental regulation of placental insulin-like growth factor (IGF)-II and IGF-binding protein-1 and -2 messenger RNA expression during primate pregnancy

Biol Reprod. 2001 Oct;65(4):1208-14. 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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blotting, Northern
  • Chorionic Villi / chemistry
  • Estradiol / administration & dosage
  • Estradiol / blood
  • Estradiol / pharmacology
  • Female
  • Fetal Weight
  • Gene Expression Regulation, Developmental* / drug effects
  • 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
  • RNA, Messenger / analysis*
  • Receptor, IGF Type 2 / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Trophoblasts / chemistry


  • Insulin-Like Growth Factor Binding Protein 1
  • Insulin-Like Growth Factor Binding Protein 2
  • RNA, Messenger
  • Receptor, IGF Type 2
  • Estradiol
  • Insulin-Like Growth Factor II