The preparation and properties of the gonad-stimulating hormone from the urine of pregnancy

Abstract

The hormone was precipitated by (NH4)2SO4. It was active physiologically in immature mice and rats. The growth rate of rats was not appreciably affected by the extract. On dialysis the hormone passed very slightly through parchment, more rapidly through collodion. In the purified solution, the following color reactions were positive: biuret, Millon, glyoxylic, and Molisch. The hormone was readily inactivated by boiling for 30 sec., by acids and alkali. Both pepsin and trypsin attacked the hormone, but quite slowly. The hormone was precipitated quantitatively by (NH4)2SO4, alcohol, acetone, "colloidal iron," or tannic acid. A method is described for purifying the hormone by means of tannic acid.