Steroid sex hormones and macrophage function: Regulation of chemiluminescence and phagocytosis

PROBLEM: Female sex hormones modulate a variety of humoral and cell-mediated immunologic functions. In this study, the effects of estrogen, progesterone, and testosterone on the chemiluminescence (CL) response and phagocytic ability of male rat peritoneal macrophages (MO) were examined. METHOD: In M∅ pretreated with 10^-2 ng/ml of 17β-estradiol (E₂) for 20 hours, the CL generated in response to phorbol myristate acetate (PMA), 1,2-dioctanoyl-rac-glycerol (C8:0), or opsonized zymosan (OZ) was significantly increased by 135%, 140%, and 136% of control values, respectively. In addition, M∅ treated with 10^-5 ng/ml or 10 ng/ml of E₂ exhibited a significantly greater PMA-or OZ-stimulated CL response than did untreated controls. RESULTS: At 10^-2 ng/ml, progesterone enhanced and testosterone reduced the CL response, but these changes were not statistically significant. In time course studies, the PMA-stimulated CL response of M∅ treated with 10^-2 ng/ml of E₂ or progesterone for 5 h was significantly less than that of the untreated group. In the presence of endotoxin (12 pg/ml), the CL response in M∅ treated with E₂ or testosterone was significantly depressed as compared to untreated controls. Phagocytosis of opsonized sheep erythrocytes also was significantly enhanced (140% to 190% of control) when M∅ were pretreated with 10^-12 M to 10^-8 M of either E₂ or progesterone. CONCLUSIONS: These findings suggest that, at physiological concentrations, E₂ is capable of modulating both CL generation and phagocytic uptake by M∅ in a manner not shared by other steroid hormones.