Relationships between Corticosterone Concentration and Season, Time of Day and Confinement in a Wild Reptile (Tuatara,Sphenodon punctatus)

Tyrrell, Claudine L.; Cree, Alison

doi:10.1006/gcen.1997.7051

Cited by 117 publications

(70 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It leads to a fivefold to tenfold increase of the basal blood corticosterone concentration (equivalent to an absolute increase of about 100ngml -1 ) above that found in natural populations [2 days to 20 days treatment (Meylan et al, 2003;Cote et al, 2006); 10 days treatment (Cote et al, 2010b) (Cote et al, 2006)]. The treatment therefore results in a corticosterone concentration similar to that naturally occurring in response to stressors, which can increase the blood corticosterone concentration of reptiles by more than tenfold from basal levels (Tyrrell and Cree, 1998).…”

Section: Experimental Corticosterone Applicationmentioning

confidence: 85%

Carotenoid-based coloration, oxidative stress and corticosterone in common lizards

Côté

Meylan

Clobert

et al. 2010

Journal of Experimental Biology

View full text Add to dashboard Cite

International audienceEnvironmental factors including stressors, health status and social context significantly affect carotenoid-based coloration. For instance, stressors may induce the diversion of carotenoids from pigmentation pathways, potentially explaining why stressed animals often exhibit reduced coloration. However, we recently showed that high blood corticosterone concentrations, which are part of the physiological stress response, are associated with increased redness of the belly in the common lizard (Lacerta vivipara). This result clearly contrasts with the findings of many studies of carotenoid-based coloration because corticosterone is believed to increase oxidative stress. Here, we examined whether these positive effects are influenced by differences in food availability. We tested the effect of high corticosterone levels on carotenoid-based coloration, antioxidant enzyme activity and oxidative damage in common lizards subject to low and high food availability. Food restriction abolished the carotenoid-based color enhancement when corticosterone concentrations in animals were high. We discuss how carotenoid-based color can honestly signal individual quality in this species and how the increased redness induced by corticosterone could be a terminal investment in an environment where long-term survival prospects are poor but not when immediate survival is endangered

show abstract

Section: Experimental Corticosterone Applicationmentioning

confidence: 85%

Carotenoid-based coloration, oxidative stress and corticosterone in common lizards

Côté

Meylan

Clobert

et al. 2010

Journal of Experimental Biology

View full text Add to dashboard Cite

show abstract

“…Plasma corticosterone levels may vary significantly over a 24-h period (Chan and Callard, 1972;Dauphin-Villernant and Xavier, 1987;Jones and Bell, 2004) (but see Tyrrell and Cree, 1998), and be confounded by the stress caused by handling the animal and obtaining the blood sample. Thus, we recorded the time of day that each sample was obtained, as well as the total duration of handling from first disturbance until the completion of blood sampling.…”

Section: (5) Do Time Of Day And/or Handling Duration Affect the Stresmentioning

confidence: 99%

How much stress do researchers inflict on their study animals? A case study using a scincid lizard, Eulamprus heatwolei

Langkilde

Shine

2006

Journal of Experimental Biology

219

140

View full text Add to dashboard Cite

SUMMARY Research on live vertebrates is regulated by ethics committees, who prohibit `excessively stressful' procedures. That judgment is based on intuition – a notoriously unreliable criterion when dealing with animals phylogenetically distant from humans. To objectively evaluate the stress imposed by research practices, we measured plasma corticosterone levels in lizards (Eulamprus heatwolei Wells & Wellington, Scincidae). Some procedures (handling and measuring, toe-clipping for identification, exposure to predator scent) did not induce significant increases in corticosterone levels, suggesting that these stimuli generated relatively little stress. However, other stimuli (testing locomotor speed, microchip implantation, blood sampling, an unfamiliar enclosure, tail autotomy, exposure to a heterospecific lizard) were more stressful, with corticosterone levels increasing only transiently in some treatments (<2 h for tail autotomy), but persisting much longer in others (14 days for microchip implantation). Overall, our data suggest that the levels of stress induced by routine laboratory procedures are no greater than those often experienced by lizards in nature; but that intuition provides a poor basis for evaluating the levels of stress induced by research. For example, toe-clipping is often criticized and sometimes banned;but our data suggest that this method is actually less stressful than the technique frequently recommended to replace it on ethical grounds (microchip implantation). Toe-clipping also was less stressful than superficially trivial manipulations such as housing the animal in an unfamiliar enclosure. More generally, we urge researchers to seek objective information on the effects of their activities on research subjects, rather than relying upon subjectivity and anthropomorphism in making these evaluations.

show abstract

“…Many species show seasonal changes in either baseline or stress-induced total CORT levels (Licht et al 1983, McLeese et al 1994, Romero et al 1997, Tyrrell & Cree 1998, Kenagy & Place 2000. Hypotheses generated to explain these seasonal changes differ, but generally it is thought that a higher level of stress-induced CORT represents a greater sensitivity to stressors, and therefore will result in a greater change in the behavior or physiology in response to the given stressor.…”

Section: Seasonality In House Sparrowsmentioning

confidence: 99%

Plasma binding proteins as mediators of corticosteroid action in vertebrates

Breuner

Orchinik

2002

Journal of Endocrinology

419

247

View full text Add to dashboard Cite

Stressors elicit a complex but variable suite of endocrine events. Comparative studies of the stress response have focused primarily on the adrenocortical response to stress, in particular the measurement of plasma levels of glucocorticoids. However, a number of other factors contribute to and modify cellular and organismal responses to glucocorticoids. Notably, plasma corticosteroid binding globulins (CBGs) can regulate the general availability of steroid to tissues, and/or direct the delivery of hormones to specific sites. In this paper, we discuss possible functions of CBG and mechanisms of CBG action, review CBG characteristics among vertebrates, and discuss our recent studies indicating that CBG may indeed modulate responses to stressors. For example, in house sparrows, we found that basal and stress-induced concentrations of total corticosteroid (cortisol or corticosterone) (CORT) vary seasonally, but CBG concentrations change proportionally, so that free CORT concentrations appear static yearround. In contrast, in white-crowned sparrows and tree lizards, CBG concentrations change under conditions when total CORT levels do not, resulting in significant changes in circulating free CORT. These differences in free CORT are masked if CBG is not accounted for. We have also found that the binding properties of CBG vary considerably between species and need to be determined empirically. Such studies led to the observation that CBG in several species may also serve as a functional androgen binding protein; this is especially important for birds, because previous studies had concluded that birds lack androgen binding globulins. We propose that consideration of CBG is paramount to understanding the role of glucocorticoids in mediating behavioral and physiological responses to stress.

show abstract

Relationships between Corticosterone Concentration and Season, Time of Day and Confinement in a Wild Reptile (Tuatara,Sphenodon punctatus)

Cited by 117 publications

References 35 publications

Carotenoid-based coloration, oxidative stress and corticosterone in common lizards

Carotenoid-based coloration, oxidative stress and corticosterone in common lizards

How much stress do researchers inflict on their study animals? A case study using a scincid lizard, Eulamprus heatwolei

Plasma binding proteins as mediators of corticosteroid action in vertebrates

Contact Info

Product

Resources

About