KINETICS OF GROWTH AND ECTOPIC PRODUCTION OF HUMAN CHORIONIC-GONADOTROPIN BY AN OVARIAN CYSTADENOCARCINOMA CELL LINE MAINTAINED INVITRO

Abstract

An established ovarian papillary cystadenocarcinoma cell line, designated 163, released immunoreactive human chorionic gonadotropin (HCG) in vitro into the culture medium. The maximal rate of this ectopic activity (10-15 ng/day per 106 cells) occurred at the onset of the logarithmic phase of cell growth and greatly exceeded the intracellular HCG content of cells approaching confluency (0.037 ng/106 cells). HCG production was not detected during the plateau phase of growth. The rate of cellular proliferation and HCG release depended on the frequency of media change in a manner suggesting that the 2 processes are interrelated and may be affected by such environmental factors as cell density, nutrient availability and the accumulation of waste products. The addition of purified HCG to the cultures had no appreciable effect on cell growth or accumulation of HCG. The release of HCG into the medium was stimulated in the presence of sodium butyrate at concentrations from 1-10 mM, despite the fact that these concentrations of butyrate resulted in a marked decrease in the cell number/culture in comparison with control media. Equivalent amounts of sodium acetate had no effect on cell growth or release of HCG.