title: Blood testosterone level: a season-dependent factor regulating immune reactivity in lizards.
abstract: An attempt to study the interaction between testosterone (Ts) and the immune system of the lizard Chalcides ocellatus led to three major findings: 1) Endogenous serum Ts levels in both males and females peak in spring and are minimal during summer; 2) Injection of Ts in either male or female lizards induces significant depletion of lymphoid elements, reduction in serum antibody titers to rat erythrocytes and increase in skin allograft survival; 3) A distinct inverse correlation between endogenous serum Ts levels and lizard immunocompetence is observed from March to September. The data obtained strongly suggested that concentration of circulating Ts is a season-related factor that is critical in defining the immune profile of lizards.
authors.affiliation: Zoology Department, Faculty of Science, Cairo University, Egypt.
authors.forename: A H
authors.initials: AH
authors.lastname: Saad
authors.forename: N A
authors.initials: NA
authors.lastname: Khalek
authors.forename: R
authors.initials: R
authors.lastname: el Ridi
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D005260:Female; D006085:Graft Survival; D007121:Immunocompetence / Q000187:drug effects / Q000502:physiology*; D008116:Lizards / Q000097:blood* / Q000276:immunology; D008297:Male; D012621:Seasons; D016038:Skin Transplantation; D013739:Testosterone / Q000097:blood* / Q000494:pharmacology
chemical_list: D013739:Testosterone