Physiological actions of corticosterone and its modulation by an immune challenge in reptiles.
Hormones are an important interface between genome and environment, because of their ability to modulate the animal's phenotype. In particular, corticosterone, the stress hormone in lizards, is known to reallocate energy from non-essential functions to affect morphological, physiological and behavioral traits that help the organism to deal with acute or chronic stressors. However, the effects of corticosterone on life history stages are still unclear primarily because of the dependence of life history stages on both internal and external factors. Using a cross-design, we tested the effect of elevated levels of exogenous corticosterone on the physiology of pregnant females in different immune contexts in a wild population of common lizards (Lacerta vivipara). Immune challenge was induced by the injection of sheep red blood cells (SRBC) and corticosterone levels were increased using a transdermal administration of corticosterone. Thereafter, reproductive traits, metabolism and cellular immune responses were measured. The elevation of corticosterone in pregnant females significantly altered reproductive and physiological performance. The corticosterone treatment decreased clutch success, juvenile size and body condition, but enhanced measures of physiological performance, such as metabolism and catalase activity. These first results reinforce the understanding of the physiological actions of corticosterone in reptiles. The data also demonstrated different direct impacts of immune challenge by SRBC on inflammatory response and antioxidant activity. The injection of SRBC stimulated the SOD activity in larger females. Finally, we demonstrated experimentally the modulation of the corticosterone action by the immune challenge on stamina and hatching date.
Meylan
Sandrine
S
Laboratoire Ecologie et Evolution, Université Pierre et Marie Curie, UMR CNRS 7625, Paris, France. smeylan@snv.jussieu.fr
Haussy
Claudy
C
Voituron
Yann
Y
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D049628:Body Size / Q000187:drug effects; D002374:Catalase / Q000378:metabolism; D003345:Corticosterone / Q000378:metabolism* / Q000494:pharmacology*; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D008116:Lizards / Q000378:metabolism; D012098:Reproduction / Q000187:drug effects; D012104:Reptiles / Q000378:metabolism; D012756:Sheep; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D003345:Corticosterone