We studied the in vitro secretion of macrophage-derived
growth factor (
MDGF) activity by peritoneal macrophages from fertile and infertile women. Peritoneal fluid was obtained from 55 women undergoing laparoscopy for evaluation and treatment of
infertility or for
tubal sterilization. Isolated macrophages were plated in tissue culture wells and incubated in Dulbecco's Modified Eagle's Medium plus 0.2%
lactalbumin hydrolyzate at 37 C for 24 h. Medium
MDGF activity was assayed by determining the ability of medium to stimulate [3H]
thymidine incorporation in BALB-c 3T3 fibroblasts. Macrophages from 23 women released significant
MDGF activity in vitro; the release was linear for up to 72 h. Among the 55 women, macrophages from 10 of 36 (28%) women with normal pelvic anatomy or
tubal occlusion/pelvic adhesions released significant
MDGF activity. In contrast, macrophages from 13 of 19 (68%) women with
endometriosis, a significantly higher proportion (P less than 0.02), released
MDGF. The finding that
endometriosis is associated with in vivo primed peritoneal macrophages that produce
MDGF in vitro may help to explain the proliferation or maintenance of endometrial tissue in the peritoneal cavity.