Differential expression and selective localization of vascular permeability factor vascular endothelial growth factor in the rat uterus during the estrous cycle

This study examines the expression of the multi-functional cytokine, vascul ar permeability factor/vascular endothelial growth factor (VPF/VEGF) in the rat uterus during early proestrus, proestrus, estrus and diestrus. Groups of ovariectomized or hypophysectomized rats served as endocrine controls. E xpression of VPF/VEGF mRNA was 2-fold greater in uteri during proestrus and estrus than in other phases of the estrous cycle. In situ hybridization te chniques indicated that VPF/VEGF mRNA expression was confined to the lumina l epithelium during proestrus, but shifted to the stromal compartment durin g estrus. Ovariectomized, hypophysectomized or diestrus rats exhibited scat tered localization of VPF/VEGF mRNA among glandular epithelium and endometr ial stromal compartments. Although VPF/VEGF mRNA was expressed throughout t he estrous cycle, but in different compartments of the endometrium dependin g on the stage of the estrous cycle, VPF/VEGF protein expression appears to be restricted to the epithelial compartment during proestrus and estrus. R esults indicate that circulating levels of gonadal steroids and LH may be a ssociated with the differential expression of VPF/VEGF mRNA and its transla tion activity in the endometrium during different stages of the estrous cyc le.