The production of placental protein 14 and interleukin 6 by human endometrial cells in culture

Epithelial and stromal cells prepared from endometrium takenat different times in the menstrual cycle were grown in primaryculture and the production of placental protein 14 (PP14) andinterleukin-6 (IL6) measured. Only the epithelial cells producedPP14. Epithelial cells from endometrium in the late secretoryphase produced significantly greater amounts of PP14 (42 ±5.8 ng/24 h) compared with that produced by cells from earlysecretory and proliferative endometrium (16 ± 1.7 and11 ± 1.9 ng/24 h respectively). PP14 production by cellsfrom endometrium at all stages in the cycle was increased byprogesterone, or progesterone and oestradiol together, whileoestradiol alone had no effect on PP14 production. The greateststimulation was seen during the early secretory phase when stimulatedlevels of PP14 reached those obtained during the late secretoryphase. IL6 production by epithelial cells also varied dependingon the phase of the menstrual cycle. More IL6 was produced bythe cells prepared from the endometrium in the proliferativephase (10.9 ± 0.56 ng/24 h) compared with that producedby cells from early and late secretory endometrium (2.5 ±0.19 and 1.45 ± 0.09 ng/24 h respectively). Additionof steroids to the media stimulated the production of IL6 bycells from proliferative and early secretory endometrium butdecreased IL6 production from cells in the late secretory phase.IL6 was also produced by stromal cells but could only be detectedin supernatants of cells prepared from late secretory endometrium,and the amounts produced (0.8 ± 0.09 ng/24 h) were lessthan that produced by epithelial cells. The production of IL6by these cells was inhibited by the addition of steroids (oestradiolalone, or oestradiol and progesterone together) to the media.The results confirm that the capacity of the epithelial cellsto produce PP14 is greatest towards the end of the secretoryphase of the cycle. They also show that although both epithelialand stromal cells are capable of producing IL6, considerablymore is produced by epithelial cells. In comparison to PP14,IL6 production is greatest during the proliferative phase ofthe cycle.