THE PRODUCTION OF PLACENTAL PROTEIN-14 AND INTERLEUKIN-6 BY HUMAN ENDOMETRIAL CELLS IN CULTURE

Epithelial and stromal cells prepared from endometrium taken at different times in the menstrual cycle were grown in primary culture and the production of placental protein 14 (PP14) and interleukin-6 (11,6) measured. Only the epithelial cells produced PP14. Epithelial cells from endometrium in the late secretory phase produced significantly greater amounts of PP14 (42 +/- 5.8 ng/24 h) compared with that produced by cells from early secretory and proliferative endometrium (16 +/- 1.7 and 11 +/- 1.9 ng/24 h respectively). PP14 production by cells from endometrium at alt stages in the cycle was increased by progesterone, or progesterone and oestradiol together, while oestradiol alone had no effect on PP14 production. The greatest stimulation was seen during the early secretory phase when stimulated levels of PP14 reached those obtained during the late secretory phase. IL6 production by epithelial cells also varied depending on the phase of the menstrual cycle. More IL6 was produced by the cells prepared from the endometrium in the proliferative phase (10.9 +/- 0.56 ng/24 h) compared with that produced by cells from early and late secretory endometrium (2.5 +/- 0.19 and 1.45 +/- 0.09 ng/24 h respectively). Addition of steroids to the media stimulated the production of IL6 by cells from proliferative and early secretory endometrium but decreased IL6 production from cells in the late secretory phase. IL6 was also produced by stromal cells but could only be detected in supernatants of cells prepared from late secretory endometrium, and the amounts produced (0.8 +/- 0.09 ng/24 h) were less than that produced by epithelial cells. The production of IL6 by these cells was inhibited by the addition of steroids (oestradiol alone, or oestradiol and progesterone together) to the media. The results confirm that the capacity of the epithelial cells to produce PP14 is greatest towards the end of the secretory phase of the cycle. They also show that although both epithelial and stromal cells are capable of producing IL6, considerably more is produced by epithelial cells. In comparison to PP14, IL6 production is greatest during the proliferative phase of the cycle.