SEX HORMONES IN THE BLOOD SERUM OF MARES

Abstract

Ovary-stimulating substances from the blood of mares, collected between 56th and 132nd day of pregnancy, were concentrated at 36[degree] C without loss of potency. The active fraction did not pass through a collodion membrane. An active fraction was removed by precipitating the serum with 14-17% Na2SO4. A more active fraction was obtained with 17-22% Na2SO4. Heating to coagulation was not harmful. Boiling rendered it less active. Results obtained by digesting serum with pepsin and trypsin were inconclusive.