The insulin-like growth factor-I system and hormone replacement therapy

Fertil Steril. 2001 Feb;75(2):282-7. doi: 10.1016/s0015-0282(00)01691-5.


Objective: To determine the effects of hormone replacement therapy on plasma concentrations of free and total insulin-like growth factor (IGF)-I, IGF binding protein (BP)-1, and IGFBP-3.

Design: Clinical study.

Setting: Gynecologic clinic at a university hospital.

Patient(s): Seventy-one postmenopausal women.

Intervention(s): Six cycles of four different hormonal replacement therapy regimens: oral conjugated estrogens, transdermal estradiol, oral conjugated estrogens and norethisterone, and transdermal estradiol and norethisterone acetate.

Main outcome measure(s): Blood samples were collected before and after treatment for measurement of free and total IGF-I, IGFBP-1, and IGFBP-3.

Result(s): Conjugated estrogen replacement therapy is associated with a decrease in plasma concentration of total IGF-I and increase in concentrations of free IGF-I and IGFBP-1. Transdermal estrogens have no effect on total and free IGF-I and IGFBP-1 concentrations. Oral norethisterone plus conjugated estrogens increased free IGF-I and IGFBP-1 concentrations but did not change IGF-I concentrations. Transdermal conjugated estrogens plus norethisterone acetate increased free IGF-I concentrations but not total IGF-I or IGFBP-1 concentrations. The plasma concentration of IGFBP-3 did not change in any group.

Conclusion(s): Alterations in total IGF-I concentration can occur depending on the route of hormone replacement therapy administration. Free IGF-I concentrations were elevated in all study groups except that treated with transdermal estrogens.

Publication types

  • Comparative Study

MeSH terms

  • Administration, Cutaneous
  • Administration, Oral
  • Blood Glucose / analysis
  • Estrogen Replacement Therapy / adverse effects*
  • Estrogens / administration & dosage
  • Estrogens, Conjugated (USP) / administration & dosage
  • Female
  • Humans
  • Insulin / blood
  • Insulin-Like Growth Factor Binding Protein 1 / blood*
  • Insulin-Like Growth Factor Binding Protein 3 / blood*
  • Insulin-Like Growth Factor I / analysis*
  • Norethindrone / administration & dosage
  • Postmenopause*


  • Blood Glucose
  • Estrogens
  • Estrogens, Conjugated (USP)
  • Insulin
  • Insulin-Like Growth Factor Binding Protein 1
  • Insulin-Like Growth Factor Binding Protein 3
  • Insulin-Like Growth Factor I
  • Norethindrone