FLOW CYTOMETRIC DETECTION AND BINDING-STUDIES OF HUMAN ENDOMETRIAL STROMAL CELL EPIDERMAL GROWTH-FACTOR RECEPTOR IN MONOLAYER-CULTURE - INFLUENCE OF PROGESTERONE

Epidermal growth factor (EGF) has been shown to modulate endometrial d ifferentiation in vivo and in vitro. Therefore, endometrial stromal ce ll EGF receptors were characterized in intact endometrial stromal cell s, cultured in vitro. The methods used for characterization were flow cytometry, binding and displacement studies, and gel electrophoresis f ollowed by autoradiography. In flow cytometry the histogram of labelle d stromal cells was identical to Caski cells, which served as a positi ve control. EGF binding revealed the typical binding hierarchy for EGF receptors, The Scatchard analysis showed a curvilinear plot with a ca lculated dissociation constant of 0.36 nM for high affinity binding si tes. In autoradiography a band of similar to 170 kDa was visualized co rresponding to the known size of the EGF receptor. The intensity of th is band was increased by pretreatment of stromal cells with 10 nM prog esterone for 4 days. Furthermore, stimulation with progesterone led to an increase in specific EGF binding activity of stromal cells by 21% compared to control. These data indicate that intact stromal cells in monolayer culture maintain specific EGF receptors, which are up-regula ted by progesterone.