Differences in urinary excretion patterns of the hLH beta core fragment inpremenopausal, perimenopausal, and postmenopausal women

Objective: The heterodimeric luteinizing hormone beta core fragment (hLH be ta cf) is a highly stable urinary analyte reflective of circulating hLH. It is measured easily because of its high molar content and has none of the m ultiple isoforms and subunit dissociation problems of LH urinary measuremen ts. As part of a long-term effort to develop new biochemical assays to stag e women during the perimenopausal transition, we have examined the patterns of urinary excretion of this metabolite of hLH in premenopausal, perimenop ausal, and postmenopausal women. Design: We measured the concentration of the hLH beta cf in 10 consecutive first morning void urine specimens from premenopausal, perimenopausal, and postmenopausal women. Day 1 of collection was the first day of menses in th e cycling women. Results: Postmenopausal women exhibited a widely fluctuating pattern of LH beta core fragment excretion, which is not correlated with hLH measured by immunofluorometric assay or with follicle-stimulating hormone measured by i mmunofluorometric assay. The postmenopausal group was easily distinguished from premenopausal women on the basis of an area-under-the-curve concentrat ion function. Perimenopausal women displayed intermediate hLH beta cf conce ntrations; some clearly were in postmenopausal ranges, and others were in t he premenopausal ranges. Conclusions: The pattern of excretion and concentrations of the hLH beta cf is significantly different between premenopausal and postmenopausal women. Perimenopausal women exhibited intermediate changes. The capability to mea sure this type of stable urinary metabolite as a reflection of changes in d ynamics of its parent circulating hormone offers new possibilities in the d evelopment and application of large-scale testing that does not require blo od sampling. (Menopause 1999;6:290-298. (C) 1999, The North American Menopa use Society.).