Plasma Steroid-Binding Globulin Mediation of Differences in Stress Reactivity in Alternative Male Phenotypes in Tree Lizards, Urosaurus ornatus

Jennings, David; Moore, Michael C.; Knapp, Rosemary; Matthews, Laura; Orchinik, Miles

doi:10.1006/gcen.2000.7564

Cited by 96 publications

(33 citation statements)

References 29 publications

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“…However, even in physiological states where the 'demand' for bioactive hormone presumably increases there is very little change in percentage bound hormone. For example, in alternate male phenotypes of tree lizards, which show differences in T-dependent aggressive behaviour, both territorial and non-territorial morphs have 99.7 and 99.8% of circulating T bound to binding globulins, respectively (Jennings et al 2000). Furthermore, even with this high level of T binding only a small fraction (7%) of the total binding globulin capacity is taken up by T. Similarly, during the adrenocortical stress response, although there are marked changes in total and free circulating glucocorticoids (e.g.…”

Section: Why Do Some Individuals Have Much Higher Hormone Titres Thanmentioning

confidence: 99%

Individual variation in endocrine systems: moving beyond the ‘tyranny of the Golden Mean’

Williams

2007

Phil. Trans. R. Soc. B

325

276

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Twenty years ago, Albert Bennett published a paper in the influential book New directions in ecological physiology arguing that individual variation was an 'underutilized resource'. In this paper, I review our state of knowledge of the magnitude, mechanisms and functional significance of phenotypic variation, plasticity and flexibility in endocrine systems, and argue for a renewed focus on inter-individual variability. This will provide challenges to conventional wisdom in endocrinology itself, e.g. re-evaluation of relatively simple, but unresolved questions such as structure-function relationships among hormones, binding globulins and receptors, and the functional significance of absolute versus relative hormone titres. However, there are also abundant opportunities for endocrinologists to contribute solid mechanistic understanding to key questions in evolutionary biology, e.g. how endocrine regulation is involved in evolution of complex suites of traits, or how hormone pleiotropy regulates trade-offs among life-history traits. This will require endocrinologists to embrace the raw material of adaptation (heritable, individual variation and phenotypic plasticity) and to take advantage of conceptual approaches widely used in evolutionary biology (selection studies, reaction norms, concepts of evolutionary design) as well as a more explicit focus on the endocrine basis of life-history traits that are of primary interest to evolutionary biologists (cf. behavioural endocrinology).

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Section: Why Do Some Individuals Have Much Higher Hormone Titres Thanmentioning

confidence: 99%

Individual variation in endocrine systems: moving beyond the ‘tyranny of the Golden Mean’

Williams

2007

Phil. Trans. R. Soc. B

325

276

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“…Recent work in the tree lizard, Urosaurus ornatus, suggest that corticosteroid-binding globulin also binds androgen with high affinity and may serve to reduce biologically active steroid levels in blood. Variation in circulating concentrations of this protein may have an important effect on the interaction of corticosteroids and androgens and their biological effects [Jennings et al, 2000].…”

Section: Resistance Hypothesismentioning

confidence: 99%

Avoiding the ‘Costs’ of Testosterone: Ecological Bases of Hormone-Behavior Interactions

Wingfield

Lynn²,

Soma³

2001

Brain Behav Evol

502

308

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A combination of laboratory and field investigations of birds has shown that expression of behavior such as territorial aggression can occur throughout the year in many species and in different life history stages. Although it is well known that testosterone regulates territorial aggression in males during the breeding season, the correlation of plasma testosterone and aggression appears to be limited to periods of social instability when a male is challenged for his territory by another male, or when mate-guarding a sexually receptive female. How essentially identical aggression is modulated in non-breeding life history stages is not fully resolved, but despite low circulating levels of testosterone outside the breeding season, expression of territorial aggression does appear to be dependent upon aromatization of testosterone and an estrogen receptor-mediated mechanism. There is accumulating evidence that prolonged high levels of circulating testosterone may incur costs that may potentially reduce lifetime fitness. These include interference with paternal care, exposure to predators, increased risk of injury, loss of fat stores and possibly impaired immune system function and oncogenic effects. We propose six hypotheses to explain how these costs of high testosterone levels in blood may be avoided. These hypotheses are testable and may reveal many mechanisms resulting from selection to avoid the costs of testosterone. It should also be noted that the hypotheses are applicable to vertebrates in general, and may also be relevant for other hormones that have a highly specialized suite of actions in one life history stage (such as breeding), but also have a limited action in other life history stages when the full spectrum of effects would be inappropriate.

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“…While this transport protein is normally considered a passive player in regulating hormone titers, the vertebrate hormone transport proteins appear to play an active role in modifying the response to stress (Fleshner et al, 1995;Alexander and Irvine, 1998;Jennings et al, 2000;see Breuner and Orchinik, 2002). In mice, stressors such as injury induce a massive rise in corticosteroids and a large reduction in corticosteroid binding globulin (CBG) mRNA abundance (D'Elia et al, 2005).…”

Section: Discussionmentioning

confidence: 98%

Effects of stress on the hemolymph juvenile hormone binding protein titers of Manduca sexta

Tauchman

Lorch

Orth

et al. 2007

Insect Biochemistry and Molecular Biology

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Plasma Steroid-Binding Globulin Mediation of Differences in Stress Reactivity in Alternative Male Phenotypes in Tree Lizards, Urosaurus ornatus

Cited by 96 publications

References 29 publications

Individual variation in endocrine systems: moving beyond the ‘tyranny of the Golden Mean’

Individual variation in endocrine systems: moving beyond the ‘tyranny of the Golden Mean’

Avoiding the ‘Costs’ of Testosterone: Ecological Bases of Hormone-Behavior Interactions

Effects of stress on the hemolymph juvenile hormone binding protein titers of Manduca sexta

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