Glycoform composition of serum gonadotrophins through the normal menstrual cycle and in the post-menopausal state

The heterogeneity of follicle stimulating hormone (FSH) and luteinizinghormone (LH) was investigated in five women aged 29.4 +/- 3.2 years (mean+/- SD) throughout their menstrual cycles and in five post- menopausalwomen aged 53.8 +/- 5.6 years. Chromatofocusing (pH range 7- 4) revealedmenstrual cycle stage- and postmenopausal-related differences in the serumgonadotrophin charge. There were differences in the proportion of FSH withan isoelectric point (pl) > 4.3 across phases of the menstrual cycle (P= 0.019): midcycle (MC) 50%; early to mid-follicular (EMF) 36%; latefollicular (LF) 37%, luteal (L) 29% and following the menopause (PM) 17%.There was no significant difference in the proportion of LH with pl >6.55 between midcycle (53%) and EMF, LF or L phases (36, 43 and 32%respectively); although all were greater than that found in the menopause(13%). Concanavalin A chromatography revealed less (P < 0.005) complexFSH and LH glycoforms at midcycle (63 and 13%) than in the EMF, LF and Lphases (90 and 18; 90 and 20 and 93 and 24% respectively). Menopausalgonadotrophins were least complex (FSH 34%, LH 4%). There was a directrelationship between serum FSH and FSH pl/complexity, and less acidic FSHwas associated with reduced FSH complexity. Increased oestradiol wasassociated with basic FSH isoforms during the menstrual cycle and reducedfollicular phase FSH complexity. We conclude that changes in gonadotrophinglycoforms occur through the menstrual cycle which are related to changesin the prevailing steroid environment. Following the menopause oestrogenicloss resulted in acidic, relatively simple glycoforms.