Ultrafiltration and Displacement Chromatography

Although apparently the first effective parathyroid extract was prepared by Moussu in 1898, some time elapsed before Hanson (1926) and Collip (1925) clearly demonstrated that an active extract of consistent potency could be prepared by using hot dilute hydrochloric acid. Since that time there have been a number of attempts to purify such extracts further. Some further purification was achieved by Ross & Wood (1942) and L'Heureux, Tepperman & Wilhehni (1947) by means of anmonium sulphate fractionation and fractional precipitation with acetone respectively. Several brief reports, including the one of Handler, Cohn & Dratz (1954), have appeared on the unsuccessful attempts to use chromatography for isolation ofthe active principle. Because they felt that initial extraction with hydrochloric acid might be disadvantageous in later purification procedures, Davies & Gordon (1955) adopted acetic acid as the extracting agent. They showed that the active principle could be obtained by extraction with 80% acetic acid, and further demonstrated that 50-65% ofthe extracted hormonal activity would pass a cellophan membrane during ultrafiltration at pH 2-4. Their most potent preparations had a specific activity comparable with, or slightly greater than, those of L'Heureux et al. (1947). The studies reported in this communication are concerned with an evaluation of these two acid extraction procedures and the further purification of the extracts by fractional precipitation with acetone, ultrafiltration, and displacement chromatography from ion-exchange resins. By these means