KERATINOCYTE GROWTH-FACTOR EXPRESSION BY THE BOVINE CORPUS-LUTEUM

Communication between cells of the corpus luteum (CL) is thought to be necessary for normal luteal function. Keratinocyte growth factor (KGF ) is produced by mesenchymally derived cells in numerous tissues and a cts on epithelial cells. In bovine follicles, theca cells produce KGF, which can stimulate granulosa cell proliferation. Whether KCF is prod uced by ovarian cells after luteinization is unknown. Our objective wa s to determine whether KGF mRNA and protein were present in bovine lut eal tissue, and if so, to determine what type(s) of luteal cells conta ins KCF. CL (n = 3-4/day) were obtained from specific days throughout diestrus. Presence of KCF mRNA in CL was determined using a porcine KG F anti-sense cRNA probe. Northern analyses of luteal tissue poly(A)(+) RNA revealed a single transcript (similar to 2.0 kilobases), the quan tity of which did not change throughout diestrus. Western analysis rev ealed an immunoreactive band (28 kDa) in luteal tissues and theca cell homogenates that was absent from granulosa cell homogenates. Immunocy tochemistry showed KCF predominantly in theca and small luteal cells. Results indicate that bovine CL produce and contain KCF, which is prim arily localized in small luteal cells. Therefore, KCF may participate in paracrine communication within the bovine CL.