Occurrence of postmenopausal-like acidic follicle-stimulating hormone (FSH) isoforms precedes the rise of FSH before menopause.

OBJECTIVE: To assess the glycoform distribution patterns of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) during the menstrual cycle at different ages and FSH levels, after menopause, and with premature ovarian failure (POF).
DESIGN: Controlled clinical study.
SETTING: Healthy volunteers in an academic research environment. PATIENT(S): Women aged 20 to 25 years with normal early follicular (EF) serum FSH (<10 IU/L), women aged 40 to 45 years with normal or increased EF serum FSH, postmenopausal women, and women with POF. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): FSH and LH glycoform distributions as assessed by chromatofocusing. RESULT(S): In both postmenopausal and in women with POF, more acidic FSH glycoforms were found compared with young cyclic premenopausal women. In women aged 40 to 45 years with normal FSH levels, these acidic glycoform profiles already showed a statistically significant difference from the younger women. This difference was to attributable to the early follicular and luteal cycle phases. Overall, during aging and after ovarian failure, FSH becomes more acidic, a difference that is already statistically significantly detectable in premenopausal, older women before FSH rises. This is not seen for LH glycoforms. CONCLUSION(S): The occurrence of postmenopausal-like acidic FSH isoforms precedes the rise of FSH before menopause.