Characterization of placental luteinizing hormone-releasing factor-like material.

High pressure liquid chromatography (HPLC) and radioimmunoassay were employed to characterize luteinizing hormone-releasing factor (LRF)-like material in the human placenta. Methanol extracts of the placenta were washed with acetic acid and chloroform, further purified on coarse octadecylsilane columns, fractionated on HPLC, and tested by radioimmunoassay. In HPLC, placental LRF had the same retention time as synthetic LRF, and such fractions gave an inhibition curve which was parallel to that of synthetic LRF in radioimmunoassay. It is concluded that human placental LRF is similar or identical to LRF in the central nervous system.