Biological Actions of Steroid Hormones in Nonmammalian Vertebrates

Jones, Ian; Bellamy, D.; Chan, D; Follett, B. K.; Henderson, Ian; Phillips, J. G.; Snart, R.S.

doi:10.1016/b978-0-12-370350-7.50012-1

Cited by 28 publications

(6 citation statements)

References 336 publications

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“…The stress response hormone corticosterone provides a mechanistic link because it is known to increase foraging activity and fat deposition (Astheimer et al . 1989; Wingfield & Silverin 1986; Astheimer, Buttemer & Wingfield 1992), while also causing muscle protein breakdown (Chester‐Jones et al . 1972) if present chronically.…”

Section: Discussionmentioning

confidence: 99%

Annual variation in fat storage by a migrant warbler overwintering in the Indian tropics

Katti

Price

1999

Journal of Animal Ecology

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Summary 0[ We studied fat storage in a population of greenish leaf warblers "Phylloscopus trochiloides# in southern India over four winters "0882Ð86#[ This species breeds in temperate regions and overwinters in India from October to April[ 1[ Diurnal variation in fat scores was comparable to that seen among temperate wintering passerines[ Seasonal variation was slight\ except for premigratory fattening[ There was signi_cant annual variation] in drier winters\ which were also winters of low food supplies\ fat scores were higher[ 2[ Energy metabolized overnight is unlikely to vary across winters\ and annual vari! ation in fat scores is considered a response to uncertainty of food intake on a given day[ Fat scores varied inversely with short!term rainfall\ which drives the abundance of arthropod prey[ 3[ Annual variation in fat scores was not accompanied by changes in total body mass[ This suggests that protein reserves were being compromised by increased fat deposition in dry years and o}ers an explanation for the observed delay in moult during drier winters[ These results suggest that strategies for maximizing short!term probability of survival translate into future _tness costs\ and may shape long!term life!history strategies through simple physiological processes[ Key!words] diurnal variation\ energy reserves\ Phylloscopus\ timing of moult\ winter survival strategies[ Journal of Animal Ecology "0888# 57\ 704Ð712

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Section: Discussionmentioning

confidence: 99%

Annual variation in fat storage by a migrant warbler overwintering in the Indian tropics

Katti

Price

1999

Journal of Animal Ecology

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“…Muscle protein breakdown is brought about by gluconeogenesis, the known effect of B (e.g. Chester-Jones et al 1972). When the implant was recovered from the bird ca.…”

Section: (B) Adrenocortical Response To Capture Stressmentioning

confidence: 99%

Modulation of the hypothalamic–pituitary–adrenal axis of an Arctic–breeding polygynandrous songbird, the Smith's longspur, Calcarius pictus

Meddle

Owen-Ashley

Richardson

et al. 2003

Proc. R. Soc. Lond. B

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To successfully reproduce in the Arctic, birds must modulate their neuroendocrine and behavioural systems. These adjustments include an attenuation of the stress responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis to external stimuli and a behavioural insensitivity to high corticosterone (B) levels. The HPA axis was examined in free-living territorial polygynandrous Smith's longspurs (Calcarius pictus) that migrate to breed on the Arctic tundra. Basal and stress-induced B levels were measured through the breeding season and were found to be significantly lower in females compared with males. This was not a consequence of adrenal insensitivity, because intrajugular injections of adrenocorticotrophin hormone (ACTH) enhanced B release in incubating females. In males the adrenocortical response to stress was significantly attenuated during the parental phase compared with arrival at the breeding ground. In contrast to temperate passerines, there was no significant decrease in male territorial aggressive behaviour when B was experimentally elevated, suggesting a behavioural insensitivity to glucocorticoids. This mechanism is hypothesized to increase reproductive success by preventing interruptions to parental care during transient deleterious environmental perturbations, which are often experienced in the short Arctic breeding season. Modulation of the HPA axis in this species in relation to life-history stage, lifetime reproductive success and the polygynandrous mating system is discussed.

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“…Urine can flow into the bladder from the cloaca but does not necessarily do so (Deucher, 1975). Anurans lack a renal loop of Henle; however, the bladder functions in water and electrolyte regulation (Bagrov et al, 1991;Chester-Jones et al, 1972;Erlij et al, 1992;Frings et al, 1990;Mia et al, 1991;Van der Goot et al, 1992;Whittembury et al, 1987;Yorio et al, 1991). Acetylcholine (ACh) decreases water uptake from the bladder (Bagrov et al, 1991) and causes contraction of bladder smooth muscle, which empties the bladder contents into the cloaca (Burnstock, 1963).…”

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confidence: 99%

Distribution and morphology of sacral spinal cord neurons innervating pelvic structures in Xenopus laevis

1994

J of Comparative Neurology

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Relatively little is known about the organization of neural input to pelvic viscera in amphibia. In this study, sacral spinal efferent neurons were labeled in Xenopus laevis frogs by application of horseradish peroxidase (HRP) to the tenth spinal nerve, to pelvic musculature, or to the pelvic nerve. DiI was applied to the pelvic nerve with similar results. Labeled spinal neurons were located in the intermediate gray or in the ventral horn. Neurons in the tenth dorsal root ganglion, but not in the spinal cord, were labeled after application of HRP or DiI to the pudendal nerve. The labeled neurons in the spinal cord intermediate gray were in a position comparable to that of the mammalian sacral parasympathetic nucleus (SPN). Two apparent subdivisions included 1) a medial cluster of cells with mediolaterally oriented dendrites and 2) a lateral group with dorsoventrally oriented dendrites. An intermediate group, not clearly classed with the other two, was also identifiable. In some cases, labeled tenth nerve primary afferents were seen in contact with efferent neurons of the intermediate gray. Labeled neurons in the ventral horn medial to the lateral motor column were small, with dendrites oriented mediolaterally, in a position comparable to that of the mammalian Onuf's nucleus. The peripheral targets of DiI-labeled pelvic nerve axons were the compressor cloaca muscle, cloaca, and bladder. DiI-labeled pudendal nerve axons distributed peripherally to cloacal lip and medial thigh integument. These data suggest that the pudendal nerve in amphibians is purely sensory and that both somatic and autonomic motor axons traverse the pelvic nerve.

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Biological Actions of Steroid Hormones in Nonmammalian Vertebrates

Cited by 28 publications

References 336 publications

Annual variation in fat storage by a migrant warbler overwintering in the Indian tropics

Annual variation in fat storage by a migrant warbler overwintering in the Indian tropics

Modulation of the hypothalamic–pituitary–adrenal axis of an Arctic–breeding polygynandrous songbird, the Smith's longspur, Calcarius pictus

Distribution and morphology of sacral spinal cord neurons innervating pelvic structures in Xenopus laevis

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