The inhibitory effects of beta-momorcharin on endometrial cells in the mouse.

beta-Momorcharin purified from the seeds of Momordica charantia L. suppressed the decidual response of pseudopregnant mouse uterus to mechanical stimulus. In the beta-momorcharin-treated uterus, stromal cells failed to decidualise, uterine glands distended, and a diminished cell proliferation was found in the endometrium and myometrium. beta-Momorcharin also inhibited the biosynthetic activity of the cultured endometrial cells. The rate of incorporation of 3H-thymidine, 3H-uridine and 3H-leucine was all depressed by beta-momorcharin. The termination of the early pregnancy in the mouse may have resulted from an inhibitory effect of the abortifacient protein on the differentiating endometrium.