Fractionation of Immunoreactive Human Chorionic Gonadotropin and Luteinizing Hormone by Isoelectric Focusing in Polyacrylamide Gel

Isoelectric focusing in polyacrylamide gel (IFPA) in conjunction with radioimmunoassay was employed to fractionate the immunologically active components of human luteinizing hormone (HLH) and human chorionic gonadotrophin (HCG). Some purified preparations and urine extracts from normal men, pre- and postmenopausal women, post partum women and men and women with choriocarcinoma were examined. HCG exhibited a pI of about 3 in agreement with previous results obtained by IFPA or other methods (1, 2). Urinary HLH preparations fractionated into 2 or 3 isoelectric components, characterized by pI's of 6.2, 4.2, and 2.8,1 depending on the previous purification steps used. The values of 6.2 and 4.2 are in reasonable agreement with previous findings (4, 5). The possibility of exploiting the differences in pI between HCG and HLH for the purpose of analysis of these two hormones in the presence of each other has been explored.