Relationships between insulin-like growth hormone factor-I and estradiol in reproductive aging

Fertil Steril. 1997 Apr;67(4):697-701. doi: 10.1016/s0015-0282(97)81369-6.


Objective: To evaluate gonadotropins, estrogen, and insulin-like growth hormone factor (IGF)-I and its binding proteins throughout the normal menstrual cycle and during aging within the reproductive life span.

Design: Daily blood samples were obtained from 17 normally cycling women.

Setting: Center for Fertility and Reproductive Medicine, Newark, New Jersey.

Participants: Ten women aged 19 to 34 years old and seven women aged 42 to 47 years old.

Main outcome measures: Luteinizing hormone (LH), FSH, E2, and P were assayed in daily blood samples. Early follicular, late follicular, midluteal phase, and samples taken at ovulation were also assayed for IGF-I and IGFBP-I and IGFBP-III.

Results: Follicle-stimulating hormone (FSH) increased significantly with reproductive aging. IGF-I and its binding proteins did not fluctuate through the menstrual cycle. IGF-I and its binding proteins did not change over the 28-year time span studied, in the face of significantly increased circulating estradiol associated with reproductive aging.

Conclusion: Rising E2 may be a subtle harbinger of the perimenopause. IGF-I and its binding proteins did not decrease with cycle stage or with aging during the reproductive years, perhaps because of increased estradiol stimulation of the somatotrophic axis.

Publication types

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

MeSH terms

  • Adult
  • Age Factors
  • Aging / blood*
  • Aging / physiology
  • Carrier Proteins / blood
  • Carrier Proteins / physiology
  • Estradiol / blood*
  • Estradiol / immunology
  • Estradiol / physiology
  • Female
  • Follicle Stimulating Hormone / blood
  • Follicle Stimulating Hormone / physiology
  • Gonadotropins, Pituitary / blood
  • Gonadotropins, Pituitary / physiology
  • Humans
  • Immunologic Tests
  • Insulin-Like Growth Factor I / analysis*
  • Insulin-Like Growth Factor I / immunology
  • Insulin-Like Growth Factor I / physiology
  • Menstrual Cycle / blood*
  • Menstrual Cycle / physiology
  • Middle Aged
  • Progesterone / blood
  • Progesterone / physiology
  • Reproduction / physiology*


  • Carrier Proteins
  • Gonadotropins, Pituitary
  • Progesterone
  • Estradiol
  • Insulin-Like Growth Factor I
  • Follicle Stimulating Hormone