Despite considerable evidence suggesting that both retinoids and sex steroids regulate female reproductive tract tissue the interplay of their effects has not been examined at the molecular level. Given the potential importance of interaction between these classes of compounds, we propose to test the hypothesis that retinoids have direct effects on growth and differentiation of human uterine cells in vitro and that they may modulate the effects of the sex steroids, estradiol (E2) and progesterone (P) Retinoid and steroid effects on the growth and differentiation of human endometrial and cervical cell will be examined in culture systems selected because they have been shown to promote retention of differentiated function; 1) growth as monolayers on 3T3 murine feeder cells, a system that has proven to be extremely useful in promoting epithelial cell growth and differentiation and 2) growth of recombined cultures of uterine/cervical epithelial and stromal cells on foating collagen rafts, a method that has been effectively used to enhance in vitro differentiation with a wide variety of epithelial cell types, Retention of in vivo phenotype of the cultures will be evaluated by determining various differentiation dependent markers of endometrial function that may be modulated by retinoids and steroids; 1) the cellular E2 and P receptor content, 2) the retinoid binding protein content, 30 the levels and types of cytokeratins present and 4) the content and activity of transglutaminase. Profiles obtained from the cultured cells will be compared to that observed from freshly isolated samples to assess the in vitro fidelity to the in vivo state. The results of the proposed research will provide new information concerning the interplay between these agents and will enable the design of future in vitro and in vivo studies to examine the effects of retinoids and their modulation of E2 and P effects in human uterine disease. The short-term goal of these studies is to develop basic knowledge regarding the interplay of retinoids and steroids in female reproductive tissues. The long-term goal is to determine whether adjuvant use of retinoids is available treatment modality to modify E2 and P effects in uterine disease.