SUBSTANTIAL URINARY CONCENTRATIONS OF MATERIAL RESEMBLING BETA-CORE FRAGMENT OF CHORIONIC-GONADOTROPIN BETA-SUBUNIT IN MID-MENSTRUAL CYCLE

We measured the day-to-day variations in concentrations of beta-core, luteinizing hormone (LH), and alpha-subunit in urine during the menstr ual cycle. The alpha-subunit concentrations showed a pattern similar t o that of the LH concentrations. beta-Core-like material was increased during and up to 3 to 4 days after the surge in urine LH. The urine L H concentration was associated with the presence of beta-core immunore activity during the urine LH peak. Chromatography showed that, at the peak LH concentration and at 2 days after the LH peak, beta-core immun oreactivity could be accounted for by the presence of a peptide of low molecular mass similar to the beta-core molecule of hCG, but probably originating from the degradation of LH. The prolonged excretion of go nadotropin metabolites in the midcycle must be considered when beta-co re is being assessed as a tumor marker.