Culture characteristics of human endometrial glandular epithelium throughout the menstrual cycle: Modulation of deoxyribonucleic acid synthesis by 17(β-estradiol and medroxyprogesterone acetate

OBJECTIVE: The purpose of this study was to evaluate the culture characteristics and cell proliferation of human endometrial glandular epithelial cells in primary culture on extracellular matrix and to evaluate sex steroid modulation of this process. STUDY DESIGN: We examined the culture characteristics in 53 endometrial gland preparations obtained throughout the menstrual cycle and determined the incorporation of tritiated thymidine in endometrial epithelial cells as a measure of deoxyribonucleic acid synthesis (cell proliferation) in the presence and absence of 17β-estradiol and medroxyprogesterone acetate. RESULTS: Good culture maintenance of endometrial epithelial monolayers on extracellular matrix was observed from glands derived from proliferate phase endometrium (21 of 23), whereas poor adherence and culture maintenance was observed in all 30 of specimens from the secretory phase. With 17β-estradiol treatment for 22 hours, tritiated thymidine incorporation was not different from control, but medroxyprogesterone acetate treatment for 22 hours was associated with diminished tritiated thymidine incorporation by 360 (p < 0.004). When 17β-estradiol (10^-8 mol/L) was included in the incubation medium from the time of initial culture, tritiated thymidine incorporation on day 4 was 40% of control (p < 0.006), and tritiated thymidine was not suppressed further by 22 hours of treatment with medroxyprogesterone acetate (10^-7 mol/L). In spite of cellular spread of endometrial epithelial cells to subconfluence, deoxyribonucleic acid content per well did not increase over time in culture. CONCLUSIONS: We conclude that exposure of endometrial glands to progesterone in vivo inhibits adherence and the establishment of cell monolayers cultured on a thin layer- of extracellular matrix. Because 17β-estradiol treatment in culture for 22 hours does not increase tritiated thymidine incorporation, it is possible that 17β-estradiol exerts its prolferation effect on the endometrial epithelium by an indirect action mediated by stromal cells. The effects of 17β-estradiol and medroxyprogesterone acetate on deoxyribonucleic acid synthesis in endometrial epithelial cells may represent an action on a stem cell population of dividing cells or a terminally differentiated cell population that undergoes programmed cell death.