OVARIAN IMMUNE CELLS EXPRESS GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR (GM-CSF) DURING FOLLICULAR-GROWTH AND LUTEINIZATION IN GONADOTROPIN-PRIMED IMMATURE RODENTS

To obtain clues as to whether granulocyte-macrophage colony-stimulatin g factor (GM-CSF) is related to ovarian physiology, the sites, the gen e expression and the production of GM-CSF in the ovary during follicul ar development and luteinization were studied in equine CG (eCG)-prime d immature mice and rats. During follicular development, the expressio n of GM-CSF mRNA was localized in theca-interstitial tissues, oocytes and granulosa cells of small developing follicles in mice. In the mous e ovary after ovulation, luteal tissues as well as the above component s had intense signals for GM-CSF mRNA. Mast cells, which were present mainly in the ovarian medulla, also expressed mRNA for GM-CSF in rats. Immunohistochemical analyses with two different antibodies against mu rine GM-CSF revealed that GM-CSF-like immunoreactivity was detectable mainly in theca-interstitial, luteal tissues, oocytes and mast cells. Intense GM-CSF positive cells in theca-interstitial and luteal tissues were stained with anti-CD11b antibody in mice. Messenger RNAs for GM- CSF receptor subunits were expressed in mast cells of the medulla and in luteal tissues in rat ovary. The levels of GM-CSF released into the culture media by rat ovarian dispersed cells 1-2 days after eCG treat ment were higher than those before the treatment, although no signific ant change in the levels of ovarian GM-CSF mRNA was detected by revers e transcription-polymerase chain reaction analysis. The secretion of G M-CSF was also increased by treatment of the cells with immune stimula tors such as phorbol ester, interleukin-l and lipopolysaccharide. Thes e data indicate that ovarian macrophages and mast cells in addition to theca-interstitial cells, synthesize and release GM-CSF during ovaria n cycles, and that ovarian GM-CSF secreting capacity is enhanced durin g early stages of follicular development in rodents. (C) 1998 Publishe d by Elsevier Science Ireland Ltd. All rights reserved.