Low Voltage Paper Electrophoretic Studies on Gonadotropin

Abstract

There are two kinds of gonadotropin excreted in the urine, viz., pituitary gonadotropin and chorionic gonadotropin, both of which are proteohormones. The present study was designed to investigate the electrophoretic characteristics of the two proteohormones by separating the two compounds by means of paper electrophoresis, and determining the position of the gonadotropically active component on the electrophoretic pattern by bioassay. The gonadotropin materials used in this study were as follows : Hypohorin, a freezedried anterior pituitary preparation, powdered desiccated anterior pituitary preparation, and HCG powder, a placental preparation extracted from placenta taken during the early stage of pregnancy and also from the latter stage of pregnancy. Gonadotropin in the urine was extracted by the carbowax concentration method as previously reported. Kobayashi's method of paper electrophoresis was employed in this study. Simultaneously and parallel to the gonadotropin preparation, human blood plasma of known electrophoretic characteristics was also run in order to determine the relative mobilities (R-Alb) of each fraction of gonadotropin in relation to albumin of blood plasma. The gonadotropic activity of each fraction was determined by the uterine weight method using young mice. Pituitary gonadotropin exhibited 5 staining zones and the gonadotropic active fraction was detected in the R-Alb VI and VII fractions, i.e., in the zone corresponding to the a, aspect of β-globulin fraction of human blood serum. Chorionic and placental gonadotropin also exhibited 5 staining zones. The gonadotropin active fraction was detected in the R-Alb V and VI fractions, i.e., in the zone corresponding to β-golbulin and γ-globulin fractions of human blood serum. Samples taken from the urine of pregnant women both during the first and third trimesters exhibited 4 staining zones, and gonadotropin active zone was detected in the R-Alb VI fraction, i.e., in the region corresponding to β-globulin of human blood serum. Samples taken from the urine of climacteric women by the carbowax method alone did not exhibit any staining zone; however, when the ammonia alcohol precipitation method was also used, a gonadotropin active zone was detected in the region corresponding to the β-and γ-globulin fractions of human blood serum. From the aforementioned data, it is evident that the electrophoretic of pituitary gonadotropin and chorionic gonadotropin differ with each other, i.e., they have different mobilities. The active zone of the pituitary ganodotropin lies mostly in the region corresponding to α-globulin fraction of human blood serum, and the placental gonadotropin in the region corresponding to β-and γ-globulin fractions of human blood serum. It is assumed that the gonadotropin excreted in the urine has an active core with conjugated protein.