Method of modifying serum hormone levels using purified inhibin materials

摘要

A protein which satisfies all the biological criteria which are characteristic of inhibin has been isolated from a gonadal source. The purification and characterization of inhibin and the use of the purified material to raise antibodies, the use of inhibin and said antisera in a quantative radioimmunoassay, and application in vitro and in vivo of inhibin and antibody to inhibin, are described. There is provided a purified protein, inhibin characterized in that the apparent molecular weight as determined by SDS-PAGE is 56,000+/-1,000, the isoelectric point is in the range 6.9-7.3, and the protein can bind specifically to Concanavalin A-Sepharose. Moreover, the protein includes two subunits, characterized in that their apparent molecular weights as determined by SDS-PAGE are 44,000+/-3,000 and 14,000+/-2,000, respectively. Furthermore, the isoelectric point of the 44,000 molecular weight sub-unit is in the range of 6.0-7.0. In addition, the N-terminal amino acid sequence of the two subunits are described. With regard to the purified protein, inhibin, the protein can suppress follicle stimulating hormone (FSH) but not luteinizing hormone (EACH), thyroid stimulating hormone or prolactin in an in vitro bioassay system, and the protein can be labeled with radioactive iodine. In addition to the forgoing, there is also provided a method for isolating and purifying inhibin from mammalian ovarian follicular fluid, characterized by one or more gel permeation chromatography steps; reversed-phase high performance liquid chromatography steps; preparative polyacrylamide gel electrophoresis steps; and electrophoretic elution of the purified inhibin.