LOCALIZATION, DISTRIBUTION AND SECRETION OF BETA-SUBUNIT OF HUMAN CHORIONIC-GONADOTROPIN IN NORMAL HUMAN CHORIONIC TISSUE

Glycoproteins, including human chorionic gonadotropin (hCG), though not of pituitary origin, consist of two subunits, namely α;- and β;-subunit. Wide attention has been paid to the activities of β;-subunit of those hormones not only biologically but immunologically, in regard to clinical interests. Recent studies have revealed that the specific antigenicity of hCG depends on not α;-subunit (α;-hCG) but β;-subunit (β;-hCG). This paper describes the localization, distribution and secretion process of β;-hCG in normal human chorionic tissue by fluorescent antibody technique, compared with the results that we obtained in studies of hCG previously. β;-hCG is produced in the area surrounding the cell nuclear zone of syncytiotrophoblasts. No expansion is recognized in cytotrophoblasts. Fine granular distribution is seen in cytoplasm. Fine granules are concentrated along the so-called brush border of syncytiotrophoblasts, to be secreted into intervillous space. The production sites of β;-hCG are far more clearly demonstrable than that of hCG. © 1979, JAPAN SOCIETY OF HISTOCHEMISTRY AND CYTOCHEMISTRY. All rights reserved.