STIMULATION OF CYCLIC-AMP, 17-BETA-ESTRADIOL AND PROTEIN-SYNTHESIS BYHUMAN CHORIONIC-GONADOTROPIN IN HUMAN ENDOMETRIAL CELLS

Human endometrial tissue was collected from 30-37 year old ovulatory w omen and enzymatically dispersed and processed to obtain endometrial s tromal cells, Cells (2x10(4)/well) were incubated in vitro in the abse nce (control) or presence of human chorionic gonadotrophin (HCG) (10 I U/well) either for 1 h (to determine cAMP) or for 4 h (to estimate pro tein synthesis, 17 beta-oestradiol and aromatase activity), HCG signif icantly stimulated cellular cAMP content and release in comparison to control, Both cellular accumulation and release of cAMP reached the pe ak at 10 min and then sharply declined in the absence of phosphodieste rase (PDE) inhibitor or remained steady for 1 h in the presence of PDE inhibitor, Content and release of 17 beta-oestradiol from stromal cel ls steeply increased from 30 min to 1 h and then slowly increased for 4 h in response to HCG, Incubation of cells with HCG significantly sti mulated (P < 0.01) cellular aromatase activity in comparison to contro l, HCG stimulated protein synthesis of the cells in two phases, initia lly at 15 min which remained steady for 1 h and then significantly inc reased (P < 0.01) between 1 and 2 h. The initial phase of protein synt hesis appears to be the direct effect of HCG while the later phase was due to the higher concentration of oestradiol caused by HCG, The init ial phase of protein synthesis was inhibited by cycloheximide but not by actinomycin D, whereas the later phase of protein synthesis was inh ibited both by cycloheximide and actinomycin D, Results therefore indi cate a probable mechanism of HCG action on stromal cells and demonstra te the physiological relevance of gonadotrophin receptor in human endo metrial cells reported earlier from this laboratory.