title: Progesterone inhibits glucocorticoid-induced murine thymocyte apoptosis.
abstract: Sex and sex hormones modulate immune development and responses. A primary target of their effects is the structure and cellularity of the thymus; therefore, we examined the effects of sex and sex steroids on thymocyte apoptosis. We demonstrate initially that male DBA mice have a significantly higher percentage of glucocorticoid-induced apoptotic thymocytes (46.1+/-3.8%) than their female counterparts (31.6+/-3.1%; P=0.012). We postulated that this gender difference was due to differential modulation of glucocorticoid-induced apoptosis by sex hormones such as estrogen, testosterone or progesterone. Both estrogen and testosterone increased in vitro thymocyte apoptosis. In contrast, progesterone not only inhibited spontaneous in vitro thymocyte apoptosis, but also prevented in vitro glucocorticoid-induced apoptosis. Progesterone administration also suppressed glucocorticoid-induced in vivo thymocyte apoptosis. These results suggest that anti-apoptotic effects of progesterone may influence T cell development and subsequent immune responses.
authors.affiliation: Division of Rheumatology/Molecular Immunology, L525 Clinical Sciences Building, G.V 'Sonny' Montgomery Memorial Veterans Hospital and The University of Mississippi Medical Center, Jackson, MS 39216, USA. rupus1@aol.com
authors.forename: R W
authors.initials: RW
authors.lastname: McMurray
authors.forename: J G
authors.initials: JG
authors.lastname: Wilson
authors.forename: L
authors.initials: L
authors.lastname: Bigler
authors.forename: L
authors.initials: L
authors.lastname: Xiang
authors.forename: A
authors.initials: A
authors.lastname: Lagoo
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000032:analysis; D017209:Apoptosis / Q000187:drug effects*; D003907:Dexamethasone / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D011374:Progesterone / Q000494:pharmacology*; D011980:Receptors, Progesterone / Q000032:analysis; D012727:Sex Characteristics; D013601:T-Lymphocytes / Q000187:drug effects*; D013739:Testosterone / Q000494:pharmacology
chemical_list: D017304:Annexin A5; D004967:Estrogens; D011980:Receptors, Progesterone; D013739:Testosterone; D011374:Progesterone; D003907:Dexamethasone