SPONTANEOUS AND GONADOTROPIN-RELEASING-HORMONE INDUCED HUMAN CHORIONIC-GONADOTROPIN RELEASE FROM SUPERFUSED JAR CHORIOCARCINOMA CELLS

JAR choriocarcinoma cells have retained several characteristics of nor mal trophoblasts and have been used as an in vitro trophoblast model. The superfusion system is suitable for the study of hormone synthesis and/or secretion. JAR cells were cultured and transferred to the super fusion system in order to evaluate the spontaneous hCG secretion and t he effect of GnRH. The spontaneous hCG release showed a periodic patte rn with a 48 min phase interval. In our system single cells and cell-c lusters were superfused and there is a possibility that cell to cell c onnections might have an influence on the regulation of hormone synthe sis and/or secretion. GnRH in 4 x 10(-7) M and 4 x 10(-6) M concentrat ions or 100 mM KCl caused an immediate hCG release from the JAR cells Repeated administration of GnRH resulted in a delayed hCG release whic h is probably related to the relatively small amount of hCG available from the storage granules or to the phase of spontaneous secretion.