Distribution and Partial Purification of Pituitary Gonadotropins of Human Plasma.

Abstract
The location and approximate concentration of gonadotropic activity in various fractions of human postmenopausal plasma was determined. The plasma was fractionated by means of the cold ethanol method VI of Conn and was assayed in immature female rats by estimating ovarian growth and secretory activity. Although traces of activity were found in Fractions IV-1, IV-4 and V, the bulk of the gonadotropically-active material was located in Fraction II+III. Subfractionation of Fraction II+III by successive precipitations with Zn and 20% ethanol freed the gonadotropins from the majority of the contaminating proteins.