Interaction of Progesterone and Oestradiol on Induced Leucocytic Emigration in the Sheep Uterus

Summary. Acute leucocytic responses to Escherichia coli placed in the uterine lumen were inhibited in oestrous ewes. The response was stimulated in ovariectomized ewes when they were injected with oestradiol, and was inhibited when they were injected with progesterone or with oestradiol and progesterone simultaneously. Uteri of ovariectomized ewes injected with both hormones were similar to those of oestrous ewes, being short and turgid, with high endometrial vascular porosity to circulating vital dye. The results support the suggestion that the inhibition of induced leucocytic emigration in the oestrous sheep uterus may be due to endogenous progestagen.