Subunits of bovine lutropin. Hormonal and immunological activity after separation with reversed-phase high-performance liquid chromatography.

By means of reversed-phase high-performance liquid chromatography, we have fractionated bovine lutropin (LH) standard preparations. The highly purified NIAMDD-bLH-4 was fractionated into two components, while the less pure NIH-LH-B9 revealed three distinct peaks. The eluted material was further characterized by in vitro bioassay and by homologous radioimmunoassay for bovine LH, ovine LH-alpha and ovine LH-beta subunits. The material with the shortest retention time possessed almost no LH-activity and showed a displacement curve nearly identical with that of the ovine LH-alpha subunit. The material corresponding to the second peak exhibited 6% of the original LH-activity, and its immunoreactivity was equal to that of the ovine LH-beta subunit. Furthermore, the fractions supposed to contain the alpha and the beta subunits were rechromatographed and their aminoacid contents analyzed. The results show close similarities between the rechromatographed fractions and the pure subunits.