Fibroblast growth factors 1 and 2 in the primate uterus

Fibroblast growth factors (FGF) 1 and 2 are paracrine effectors of proliferation and angiogenesis in many tissues. To elucidate potential roles for these growth factors in uterine plasticity, we used in situ hybridization histochemistry to identify the cellular sources of FGF-1 and -2 production, and immunohistochemistry to identify the cellular and extracellular deposition sites of the peptides in the primate uterus. To evaluate the effects of estradiol on uterine FGFs, uteri from ovariectomized rhesus monkeys treated with estradiol- or vehicle-containing pellets were investigated. FGF-1 and -2 mRNAs were both expressed in uterine epithelial and myometrial cells. Quantitative comparison of their mRNA levels using computerized grain counting showed no significant difference between estradiol- and vehicle-treated animals. FGF-1 immunoreactivity was detected in scattered epithelial, vascular, and myometrial cells in the vehicle-treated animals but found to be significantly more intense and widespread in estradiol-treated animals. In both conditions, FGF-1 immunostaining was predominantly nuclear. FGF-2 immunoreactivity was concentrated extracellularly in the basal lamina of both glandular and surface epithelium and was abundant and diffusely distributed within myometrial and vascular cells in both cytoplasm and nucleus. There was no apparent difference in the pattern or intensity of FGF-2 immunostaining related to estradiol treatment. These data demonstrate that major uterine cell types synthesize both FGF-1 and -2, and that the two peptides are differentially localized in uterine cellular and extracellular compartments and differentially sensitive to regulation by estradiol.