Vascular permeability in uterine endometrium and serosa was measured in eighty-three ewes by the intensity of tissue blueing after intravenous injection of trypan blue dye. Permeability was high in oestrous ewes, intermediate in luteal-phase ewes and low in ovariectomized controls.
During experimental acute infection in the uterine lumen, endometrial vascular permeability increased greatly in ovariectomized ewes, but little or not at all in luteal-phase or oestrous ewes, indicating that endogenous ovarian hormones modified the vascular response. Serosal vascular permeability increased markedly in ewes of each endocrine state. Endocrine-controlled variation in the rate of leucocytic emigration was not entirely related to endometrial vascular permeability.