Progestational hormone in human placenta

Progesterone has been isolated from human placental tissue in a yield of approximately one part per million parts of tissue. The initial step involved digesting the tissue in a sodium hydroxide solution. The alkaline digestion partially liquefied the ground tissue, liberated lipids from lipoproteins and gave a mixture with which it was very easy to work. Progesterone, contrary to the reports found in the early literature, was found to be stable to dilute sodium hydroxide at room temperature. This work indicated that the sodium hydroxide treatment may be of great importance in the isolation of the hormone from the natural tissue-protein mixture. The alkali may destroy a progesterone-protein complex which is not soluble in either. The failure of other workers to isolate progesterone from placental extracts may be due to this complex. The bioassays indicate that nearly all of the activity which was found in the lipid extract may be accounted for as progesterone. The isolation of the hormone when correlated with previous work on steroid metabolism during pregnancy gives strong evidence that the progestational hormone of the placenta is progesterone. Several types of chromatographic systems were investigated which were based on the conventional method of elution analysis. It was found that very pure preparations could be achieve by alternating absorbents and solvent systems. Acetylation of a substance which was homogeneous to chromatography gave a preparation which could be easily fractionated to give pure progesterone. The chromatographic procedures indicated that crude mixtures followed a displacement type of analysis even though an absorption analysis was being conducted according to the elution technique. In the purer mixtures this was not observed. From the standpoint of labor and volume of solvents involved, the displacement type of analysis is indicated as being a very valuable tool in isolation work.