Alpha and beta subunit immunoreactivity of reference preparations used in the radioimmunoassay of follicle stimulating and luteinizing hormones in serum.

The 2nd IRP-HMG, the 1st IS, and LER 907 have been widely used in standard FSH and LH RIA systems to measure circulating levels of FSH and LH in human serum. In these systems, the dose-response curves elicited by the preparations were parallel to each other and to that of serum samples tested. When these materials were studied in the homologous alpha and beta-hLH RIA systems, the three hormones and a serum sample used as internal control in all assays, displayed a higher degree of contamination with alpha than with beta-hLH subunits. On weight basis, the alpha/beta ratios were 18.0, 18.7, 6.7, and 13.0, for the 2nd IRP-HMG, 1st IS, LER 907 and serum, respectively. In the homologous alpha and beta hfSH RIA's, the highest contamination with alpha-hfSH was displayed by (alpha/beta ratio:10), the alpha/beta ratios for the 2nd IRP-HMG and 1st IS were 2.2 and 1.1, respectively. The serum sample contained about 6.2 ng equivalent of alpha-hFSH/ml; beta-hFSH was not detected.