We investigated the ability of interleukin 6 (IL-6) to modulate human
endometrial stromal cell growth irt vitro. Stromal cell proliferation
in response to treatment with varying concentrations of IL-6 was deter
mined. Endometrial tissue was obtained from 10 normally cycling women
during the secretory phase of their menstrual cycle. Treatment with IL
-6 resulted in a dose- and cell-density-dependent inhibition of endome
trial stromal cell proliferation in vitro. The maximal inhibition was
observed with 200 pg/ml of IL-6 and at a concentration of 10(5) cells/
well. During in-vitro culture, stromal tells produced low amounts of I
L-6 and demonstrated the presence of IL-6 receptor. These data demonst
rate that IL-6 acts as a growth-regulatory signal for human endometria
l stromal cells. We postulate that IL-6 may contribute to the maintena
nce of homeostasis in normal endometrium and that perturbation of IL-6
mediated responses may play a role in disorders of the endometrium su
ch as endometrial cancer and endometriosis.