Alpha-subunit of human chorionic gonadotropin in fluid of molar vesicles

Sera and fluid in molar vesicles from 4 patients with hydatidiform mole were analyzed for hCG and its subunits. These samples were initially chromatographed through a standardized Sephadex G-100 upward column. Starting materials and each fraction on gel filtration were radioimmunoassay in homologous hCG, hCG-alpha and hCG-beta assays. The specimens obtained from 4 patients contained primarily hCG and little hCG-beta. Immunoreactive hCG-alpha was barely detectable in sera but was clearly demonstrated in vesicle fluid from molar patients. This immunoreactive hCG-alpha was combined with [125I]hCG-beta. The combined protein, [125I]hCG and [125I]hCG-beta recombined with urinary hCG-alpha were concentrated in the superovulated rat ovary in vivo. However, [125I]hCG-alpha and [125I]hCG-beta were not taken up by the ovaries. The biosynthesis of hCG-alpha are discussed.