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

• Published in: Fertility and sterility Vol. 67; no. 4; pp. 697 - 701
• Main Authors: Blake, Emily J., Adel, Tovaghgol, Santoro, Nanette
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY Elsevier Inc 01.04.1997; Elsevier Science
• Subjects: Adult; Age Factors; Aging - blood; Aging - physiology; Biological and medical sciences; Carrier Proteins - blood; Carrier Proteins - physiology; Estradiol - blood; Estradiol - immunology; Estradiol - physiology; estrogen; Female; Follicle Stimulating Hormone - blood; Follicle Stimulating Hormone - physiology; Fundamental and applied biological sciences. Psychology; Gonadotropins, Pituitary - blood; Gonadotropins, Pituitary - physiology; Hormone metabolism and regulation; Humans; IGF binding proteins; IGF-I; Immunologic Tests; Insulin-Like Growth Factor I - analysis; Insulin-Like Growth Factor I - immunology; Insulin-Like Growth Factor I - physiology; Mammalian female genital system; Menstrual Cycle - blood; Menstrual Cycle - physiology; Middle Aged; perimenopause; Progesterone - blood; Progesterone - physiology; Reproduction - physiology; Reproductive aging; Vertebrates: reproduction; perimenopause; IGF-I; estrogen; IGF binding proteins; Reproductive aging; Human; Reproduction; Senescence; Menstrual cycle; Insulin growth factor binding protein; Menopause; Estrogen; Female; Gonadotropin; Insulin like growth factor 1
• ISSN: 0015-0282; 1556-5653
• 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, E 2, 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 E 2 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.