DISTRIBUTION OF F4 80-POSITIVE CELLS IN DEVELOPING OVARIES IN THE MOUSE/

The mature ovary contains a large number of macrophages, In the presen t study, the distribution of macrophages in murine ovaries at various developmental stages was immunohistochemically studied using a monoclo nal antibody against F4/80, a highly specific antigen of murine macrop hages, The results showed that definite F4/80-positive stains were har dly detectable in ovaries on day 0 after birth, On day 7, a few F4/80- positive cells could be identified between the developing follicles, T he positive stains were irregular in shape and showed little physical contact with the primordial or primary follicles, By days 14 and 21, w hen the theca cell layers of growing follicles were developing, the po sitive cells had extended or elongated to surround the cell layer. On day 28, besides the presence of elongating positive cells surrounding the growing follicles, irregularly shaped F4/80-positive cells became apparent in the interstitium between the growing follicles and also in the capsular tissues. Thereafter, positive cells with stellate appear ance were detected in the corpora lutea, which first developed around 6 weeks of age. Although the positive cells were homogenously distribu ted in the corpora lutea in virgin adults, only a few sporadic positiv e cells were found there in pregnant mice. However, the positive cells infiltrated into the corpora lutea again in the postpartum period. Th ese results show that ovarian macrophages exhibit dramatical changes i n their distribution from neonatal to postpartum periods.