Endocrine changes in dasyurid marsupials with differing mortality patterns

McDonald, I. R.; Lee, A.K.; Bradley, A. J.; Than, Khin Aye

doi:10.1016/0016-6480(81)90004-6

Cited by 117 publications

(77 citation statements)

References 9 publications

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“…The MCBC of the plasma was measured by a saturation ligand method (McDonald et al 1981). Briefly [ 3 H]cortisol, diluted in non-radioactive cortisol to known specific activity 5-to 20-fold in excess of the expected capacity was added to 10 µl plasma (analyzed in duplicate).…”

Section: Mcbc Assaymentioning

confidence: 99%

Increased corticosteroid binding capacity of plasma albumin but not of corticosteroid-binding globulin caused by ACTH-induced changes in free fatty acid concentrations in snowshoe hares and rabbits

Boonstra

Tinnikov²

1998

Journal of Endocrinology

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Free fatty acids (FFAs) are rapidly mobilized by ACTH and have been shown to be potent endogenous modulators of steroid-protein interactions. We increased FFA in lagomorphs by ACTH and then separated the transient increase in glucocorticoid binding capacity of plasma into that accounted for by changes in binding to albumin and to corticosteroid-binding globulin (CBG). Sequential injections of dexamethasone and ACTH into both snowshoe hares and laboratory rabbits resulted in the rapid mobilization of FFA only after the ACTH injection. The maximum corticosteroid binding capacity increase paralleled that of the FFA increase in both species. In rabbits, CBG levels remained constant over the duration of the experiment. Corticosterone binding by rabbit albumin increased in a dose-dependent fashion in response to increases in FFA (oleic and linoleic acid) concentrations. Finally, by stimulating FFA release in snowshoe hares with ACTH and separating the increase in corticosteroid binding capacity through selective denaturing of CBG by heat, we determined that the increase in plasma binding capacity was a response to changes in binding by albumin, not CBG. Thus FFA released in response to stressors in lagomorphs may effect short-term increases in steroid binding.

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Section: Mcbc Assaymentioning

confidence: 99%

Increased corticosteroid binding capacity of plasma albumin but not of corticosteroid-binding globulin caused by ACTH-induced changes in free fatty acid concentrations in snowshoe hares and rabbits

Boonstra

Tinnikov²

1998

Journal of Endocrinology

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“…A similar adrenocortical mechanism impacting immune function has been proposed for the post-mating deaths of males from dasyurid marsupials (Antechinus stuartii and A. favipes) of eastern Australia (Bradley et al 1980;McDonald et al 1981), although in the larger dasyurid Dasyurus hallucatus, there is no evidence of elevated corticosteroid levels during male die-off (Oakwood et al 2001). These results do not however support the primacy of cortisol as the trigger of death suggested by others.…”

Section: Ratio Of Sex Steroid/gonadotropin As a Measure Of Dyotic Sigmentioning

confidence: 68%

“…Together, these results suggest that the dysregulation of hormones of the HPG axis, those hormones that normally maintain tissue structure and function, is more likely driving semelparous species from the gene pool (Oakwood et al 2001;Woods and Hellgren 2003). However, which changes in sex hormones drive death remains to be elucidated; elevations in testosterone have been reported for dasyurid and didelphid marsupial species (Bradley et al 1980;McDonald et al 1981;Oakwood et al 2001), while there is a precipitous decline in testosterone concentrations and survivability of male R. fuscipes, which do not live long beyond the breeding season (Table 3; McDonald et al 1988b). Further research in other iteroparous species is required to validate the elevated post-reproductive dyotic signals observed in male and female sockeye salmon.…”

Section: Ratio Of Sex Steroid/gonadotropin As a Measure Of Dyotic Sigmentioning

confidence: 94%

Does the degree of endocrine dyscrasia post-reproduction dictate post-reproductive lifespan? Lessons from semelparous and iteroparous species

et al. 2017

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Post-reproductive lifespan varies greatly among species; human post-reproductive lifespan comprises~30-50% of their total longevity, while semelparous salmon and dasyurid marsupials post-reproductive lifespan comprises <4% of their total longevity. To examine if the magnitude of hypothalamic-pituitarygonadal (HPG) axis dyscrasia at the time of reproductive senescence determines post-reproductive lifespan, we examined the difference between pre-and postreproductive (1) circulating sex hormones and (2) the ratio of sex steroids to gonadotropins (e.g., 17β-estradiol/follicle-stimulating hormone (FSH)), an index of the dysregulation of the HPG axis and the level of dyotic (death) signaling post-reproduction. Animals with a shorter post-reproductive lifespan (<4% total longevity) had a more marked decline in circulating sex steroids and corresponding elevation in gonadotropins compared to animals with a longer post-reproductive lifespan (30-60% total longevity). In semelparous female salmon of short post-reproductive lifespan (1%), these divergent changes in circulating hormone concentration postreproduction equated to a 711-fold decrease in the ratio of 17β-estradiol/FSH between the reproductive and post-reproductive periods. In contrast, the decrease in the ratio of 17β-estradiol/FSH in iteroparous female mammals with long post-reproductive lifespan was significantly less (1.7-34-fold) post-reproduction. Likewise, in male semelparous salmon, the decrease in the ratio of testosterone/FSH (82-fold) was considerably larger than for iteroparous species (1.3-11-fold). These results suggest that (1) organisms with greater reproductive endocrine dyscrasia more rapidly undergo senescence and die, and (2) the contribution postreproduction by non-gonadal (and perhaps gonadal) tissues to circulating sex hormones dictates postreproductive tissue health and longevity. In this way, reproduction and longevity are coupled, with the degree of non-gonadal tissue hormone production dictating the rate of somatic tissue demise post-reproduction and the differences in post-reproductive lifespans between species.

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“…The fact that such adaptations have their physiological costs and may even fail, is nicely illustrated in field studies by BRADLEY et al (1980) and McDONALD et al (1981) on populations of small marsupial spieces. They concluded that stess induced by aggressive interaction during the mating season resulted in strong neuroendocrine changes with consequent immunosuppression and death from gastrointestinal haemorrhage and infection by parasites and microorganisms.…”

Section: Introductionmentioning

confidence: 98%

Individual Differences in Disease Susceptibility as a Possible Factor in the Population Dynamics of Rats and Mice

Koolhaas

Oortmerssen

1987

Neth J Zool

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SUMMARYFactors affecting health and disease are somewhat neglected in the study of the dynamics of mammalian populations. The present paper summarizes a number of studies on social stress in rats and mice. Social situations induce classical stress responses in terms of corticosterone and catecholamines. More important is the fact that there is a considerable individual differentiation in the magnitude of the responses in relation to the behavioural stategy in a social situation. These physiological differences render individuals differentially susceptible for stress pathologies such as cardiovascular diseases and immune deficiencies. Moreover, the behavioural strategy largely determines the position of an animal in the social structure and hence the frequency of behavioural and physiological activation. The data suggest that the individual behavioural and physiological reactivity determine in interaction with the social environtment the susceptibility for diseases. The relevance of these observations for the dynamics of a population is discussed.

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Endocrine changes in dasyurid marsupials with differing mortality patterns

Cited by 117 publications

References 9 publications

Increased corticosteroid binding capacity of plasma albumin but not of corticosteroid-binding globulin caused by ACTH-induced changes in free fatty acid concentrations in snowshoe hares and rabbits

Increased corticosteroid binding capacity of plasma albumin but not of corticosteroid-binding globulin caused by ACTH-induced changes in free fatty acid concentrations in snowshoe hares and rabbits

Does the degree of endocrine dyscrasia post-reproduction dictate post-reproductive lifespan? Lessons from semelparous and iteroparous species

Individual Differences in Disease Susceptibility as a Possible Factor in the Population Dynamics of Rats and Mice

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