STUDIES ON PITUITARY FOLLITROPIN .1. IMPROVED PROCEDURE FOR THE ISOLATION OF HIGHLY POTENT OVINE HORMONE

An improved method of isolation of ovine pituitary follitropin has been described. The method involves extraction of frozen glands at pH 9.0 in presence of an enzyme inhibitor, metaphosphoric acid precipitation at two stages, ammonium sulfate fractionation, glycoprotein fractionation, ion exchange chromatography on SP-C50 followed by affinity chromatography on concanavalin A-Sepharose, and filtrations on Sephadex G-100. A highly active preparation with a yield of about 11 mg/kg is obtained and has an activity of about 110 × NIH-FSH-S10 standard in the human chorionic gonadotropin (HCG)-augmentation assay in rats. Its lutropic activity as estimated by specific in vitro bioassay and radioreceptor assay was about 0.005-0.01 unit (NIH-LH-S19)/mg. It is more acidic than lutropin and thyrotropin. Its amino acid composition and carbohydrate content has been analyzed. Its isoelectric point is approximately pH 4.9. © 1979.