Pituitary dysfunction in recently post-menopausal women. Nottingham EPIC Study Group

Area of Science:

• Endocrinology
• Reproductive Medicine
• Bone Metabolism

Background:

• Follicle-stimulating hormone (FSH) levels are typically elevated post-menopause.
• Inappropriately low FSH in some post-menopausal women suggests potential hypothalamo-pituitary dysfunction.
• Bone loss prevention studies require accurate assessment of menopausal status.

Purpose of the Study:

• To investigate pituitary function in recently post-menopausal women with unexpectedly low FSH levels.
• To assess the relationship between pituitary hormone responses and bone mineral density.

Main Methods:

• Prospective study involving 47 healthy post-menopausal women within 10 years of menopause.
• Pituitary stimulation tests using gonadotropin-releasing hormone (GnRH) and thyrotropin-releasing hormone (TRH).
• Measurement of FSH, luteinizing hormone (LH), prolactin, and thyroid-stimulating hormone (TSH) responses; assessment of bone mineral density.

Main Results:

• Women with low FSH showed significantly impaired responses to GnRH/TRH for FSH, LH, and prolactin.
• Thyroid-stimulating hormone (TSH) secretion was not significantly impaired.
• Despite higher free estradiol index and body mass, bone mineral density did not differ between groups.

Conclusions:

• Follicle-stimulating hormone (FSH) levels are not always elevated post-menopause; caution is advised when using FSH alone to determine menopausal status.
• Abnormally low FSH in post-menopausal women may indicate subclinical pituitary impairment affecting prolactin, FSH, and LH.
• This pituitary dysfunction did not appear to impact bone mineral density in the study group.