Hormonal regulation of macrophage collagenase activity

Abstract

Whereas peritoneal macrophages from nonpregnant guinea pigs were stimulated in vitro by endotoxin to produce collagenase on the second day of culture, those from pregnant guinea pigs were incapable of this response. However, if the cells from pregnant animals were preincubated for one day prior to endotoxin stimulation, collagenase activity could be detected. Injection of either estrogen or progesterone into guinea pigs at doses comparable to those found during pregnancy prior to removal of the peritoneal cells also inhibited the in vitro stimulation of collagenase production. The addition of these hormones in vitro revealed that at 5 × 10 −6 M estrogen and progesterone inhibited 53% and 100% respectively of the collagenase activity. Addition of both hormones at a final concentration of 5 × 10 −7 M of each inhibited 87% of the activity indicating a synergistic effect since this concentration of either hormone alone was ineffective.