HUMAN CHORIONIC GONADOTROPIN-LIKE AND BETA-CORE-LIKE MATERIALS IN POSTMENOPAUSAL URINE

In addition to human chorionic gonadotrophin (hCG), the urine of pregnant women contains a small molecular weight form of the hCG-β subunit known as β-core. Human CG-like material has been described in tissues, serum and urine of normal man, particularly in postmenopausal women. We examined different urine preparations from postmenopausal women to determine whether β-core-like material, as well as hCG-like material, could be detected. We studied an acetone extract of a pool of 11 litres of postmenopausal urine, three different commercial preparations of human menopausal gonadotrophins and two commercial preparations of 'pure' FSH. After Sephadex G-100 chromatography of these various postmenopausal urine extracts, fractions were assayed using four assay systems to detect hCG, β-core, LH and FSH immunoreactivities. Human CG immunoreactivity was readily detected in all urinary extracts and it eluted in a position indistinguishable from that of purified hCG. In addition to this hCG-like material, all urinary extracts, except the commercial 'pure' FSH preparations, contained material which reacted in the β-core radioimmunoassay. This β-core immunoreactive material eluted from Sephadex G-100 in a position corresponding to that of purified pregnancy-derived β-core. We conclude that the urine of postmenopausal women contains material resembling the β-core molecule found in pregnancy urine. The origin of this β-core-like material remains to be determined, and its presence will have an impact on the application of urinary β-core as a tumour marker.