Abstract
Further fractionation of the active substances extracted from the human placenta at the later stage of pregnancy was carried out by urtracentrifugation and two fractions, Fractions UA and UB, were obtained.
These substances are glycoproteins, namely Fraction UA contains fructose and glucose, whereas Fraction UB contains mannose and galactose.
Fraction UA contains mainly a component with sedimentation coefficient of 2.4 (2.4 S-component) and Fraction UB contains mainly that of 4.3 (4.3 Scomponent). The 4.3 S-component possesses the activity of increase of the size and number of fatty granules in the crop milk of pigeons. The 2.4 S-component possesses the activity on the proliferation of mucous membrane of crop-gland.
The 2.4 S-and 4 3 S-components have the molecular weights of 45, 000 and 80, 000, respectively. These components, therefore, seem to be different from the pituitary lactogenic hormone.
