Human chorionic gonadotrophin-like and beta-core-like materials in postmenopausal urine

Abstract

In addition to human chorionic gonadotrophin (hCG), the urine of pregnant women contains a small molecular weight form of the hCG-beta subunit known as beta-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 beta-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, beta-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 beta-core radioimmunoassay. This beta-core immunoreactive material eluted from Sephadex G-100 in a position corresponding to that of purified pregnancy-derived beta-core. We conclude that the urine of postmenopausal women contains material resembling the beta-core molecule found in pregnancy urine. The origin of this beta-core-like material remains to be determined, and its presence will have an impact on the application of urinary beta-core as a tumour marker.