HLH BETA-CORE FRAGMENT IMMUNOREACTIVITY IN THE URINE OF OVULATING WOMEN - A SENSITIVE AND SPECIFIC IMMUNOMETRIC ASSAY FOR ITS DETECTION

Recently, we isolated an hLH beta core fragment (hLH beta cf) from hum an pituitaries. This molecule is homologous to the hCG beta core fragm ent (hCG beta cf), which may be a marker of normal pregnancy, Down syn drome, and certain cancers. We now report antibodies to the hLH beta c f, four of which have been applied in sensitive immunoradiometric assa ys for urinary measurements. One of the antibodies recognizes an epito pe on the hLH beta cf, which is not present on the hCG beta cf, hLH, o r hLH beta. This specific hLH beta cf antibody acts cooperatively with other newly-developed antibodies reported here to produce an assay wi th a sensitivity of 1 fmol/ml of hLH beta cf. The specificity of these new IRMA systems will make it possible to measure the hLH beta cf in urine in the presence of hLH, hLH beta, or the hCG beta cf. Although t he hLH beta cf used to develop specific antibodies was purified from p ituitaries, the assays developed recognize this metabolite in urine. M easurements of heterodimeric hLH as compared to hLH beta cf in the uri ne of cycling women indicated that the concentration of hLH beta cf ro se as high as 6-7 times the concentration of hLH starting a day after the midcycle surge. The new measuring systems allow the precise quanti tation of this hLH metabolite in urine.