title: Effects of 17alpha-ethinylestradiol on immune parameters in the lizard Sceloporus occidentalis.
abstract: We examined the effect of 17alpha-ethinylestradiol on immunity of the Western fence lizard, Sceloporus occidentalis. Injection of 17alpha-ethinylestradiol resulted in dose-dependent suppression of peripheral blood leukocyte levels as determined by cell counts, whereas total spleen cell levels were decreased only at higher doses of 17alpha-ethinylestradiol. In contrast, spleen cell proliferation was enhanced by 17alpha-ethinylestradiol as measured by reduction of MTT to formazan following a two-way mixed lymphocyte reaction. Antibody responses were unaffected. Effects on peripheral blood leukocyte levels and spleen cell proliferation similar to those observed in response to injection of 17alpha-ethinylestradiol were observed following injection of a single dose of hydrocortisone. However, injection of lizards with 17alpha-ethinylestradiol did not result in a significant increase in serum cortisol. Results of this study suggest that exposure of Western fence lizards to 17alpha-ethinylestradiol leads to decreased numbers of circulating leukocytes and total spleen cell numbers and the enhancement of spleen cell proliferation in a two-way mixed lymphocyte reaction. These effects probably involve mechanisms other than or in addition to the induction of cortisol release.
authors.affiliation: Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA. burnham@okstate.edu
authors.forename: D Kim
authors.initials: DK
authors.lastname: Burnham
authors.forename: Amanda
authors.initials: A
authors.lastname: Lackey
authors.forename: Michelle
authors.initials: M
authors.lastname: Manering
authors.forename: Elin
authors.initials: E
authors.lastname: Jaensson
authors.forename: Jamie
authors.initials: J
authors.lastname: Pearson
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Tyler
authors.forename: David
authors.initials: D
authors.lastname: Melson
authors.forename: Larry G
authors.initials: LG
authors.lastname: Talent
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D045166:Estradiol Congeners / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D006384:Hemagglutination / Q000187:drug effects*; D006854:Hydrocortisone / Q000097:blood; D007958:Leukocyte Count; D008116:Lizards / Q000276:immunology*; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D013154:Spleen / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000494:pharmacology
chemical_list: D045166:Estradiol Congeners; D014874:Water Pollutants, Chemical; D004997:Ethinyl Estradiol; D006854:Hydrocortisone