Growth hormone and proclatin in avian species

Scanes, Colin G.; Harvey, Steven

doi:10.1016/0024-3205(81)90264-2

Cited by 49 publications

(10 citation statements)

References 47 publications

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“…As in mammals, circulating prolactin levels have classically been reported to increase in response to stress in early studies of birds Scanes and Harvey, 1981). For instance, prolactin levels increase in response to cold or immobilization stress in domestic birds (Harvey et al, 1977(Harvey et al, , 1978Opel and Proudman, 1986) and the stress of a high parasite load or an infection results in increased prolactin levels in domestic fowls (Chadwick et al, 1985;Davison et al, 1985).…”

Section: Stage-dependent Prolactin Stress Responsementioning

confidence: 97%

Does prolactin mediate parental and life-history decisions in response to environmental conditions in birds? A review

Angelier

Wingfield

Tartu

et al. 2016

Hormones and Behavior

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This article is part of a Special Issue "Parental Care". In vertebrates, adjustments of physiology and behavior to environmental changes are often mediated by central physiological mechanisms, and more specifically by hormonal mechanisms. As a consequence, these mechanisms are thought to orchestrate life-history decisions in wild vertebrates. For instance, investigating the hormonal regulation of parental behavior is relevant to evaluate how parents modulate their effort according to specific environmental conditions. Surprisingly and despite being classically known as the 'parental hormone', prolactin has been overlooked in birds relative to this context. Our aim is to review evidence that changes in prolactin levels can mediate, at least to some extent, the response of breeding birds to environmental conditions. To do so, we first examine current evidence and limits for the role of prolactin in mediating parental behavior in birds. Second, we emphasize the influence of environmental conditions and stressors on circulating prolactin levels. In addition, we review to what extent prolactin levels are a reliable predictor of breeding success in wild birds. By linking environmental conditions, prolactin regulation, parental behavior, and breeding success, we highlight the potential role of this hormone in mediating parental decisions in birds. Finally, we also review the potential role of prolactin in mediating other life history decisions such as clutch size, re-nesting, and the timing of molt. By evaluating the influence of stressors on circulating prolactin levels during these other life-history decisions, we also raise new hypotheses regarding the potential of the prolactin stress response to regulate the orchestration of the annual cycle when environmental changes occur. To sum up, we show in this review that prolactin regulation has a strong potential to allow ecological physiologists to better understand how individuals adjust their life-history decisions (clutch size, parental behavior, re-nesting, and onset of molt) according to the environmental conditions they encounter and we encourage further research on that topic.

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Section: Stage-dependent Prolactin Stress Responsementioning

confidence: 97%

Does prolactin mediate parental and life-history decisions in response to environmental conditions in birds? A review

Angelier

Wingfield

Tartu

et al. 2016

Hormones and Behavior

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“…In vivo, TRH stimulates the incorporation of 32 P into (3) and release of 131 I from the thyroid (4,5). In addition, TRH has also been shown to be a potent releaser of GH in birds both in vivo and in vitro (6,7). In mammals, stimulatory effects of TRH on thyroid hormones (via TSH), GH, and PRL have been reported, as well as growth-promoting effects of the hormone.…”

mentioning

confidence: 94%

Thyrotropin-Releasing Hormone Stimulates Body Weight Gain and Increases Thyroid Hormones and Growth Hormone in Plasma of Cockerels

1984

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The effect of TRH on growth in 4-week-old cockerels was examined in two separate experiments. Daily injection of TRH via the brachial vein stimulated growth in 4-week-old cockerels over 17 days of treatment in the first experiment and over 25 days in the second. In the first experiment, TRH at 1.0 micrograms and 10.0 micrograms/bird caused significant (P less than 0.05) increases of 12.0% and 12.4%, respectively, in growth rate, whereas in the second experiment, only the 1.0 micrograms/bird level of TRH caused an increase (P less than 0.05). In each experiment, the increase in body weight gain was not TRH dose dependent, and neither feed consumption nor feed efficiency was affected. Possible involvement of pituitary hormones in TRH-stimulated growth in cockerels was studied in a separate experiment, and the effects of TRH on plasma T3, T4, and GH were examined. TRH was given iv at 0.1, 1.0, and 10.0 micrograms/bird daily for 5 days, and plasma T3, T4, and GH concentrations were measured 15, 60, and 180 min postinjection by RIA on days 1, 3, and 5. The responses of T3 and T4 to TRH were greatest on day 1, were diminished by days 3 and 5, and were not dose-related. Significant, not dose-related, elevations of plasma GH concentrations were obtained at all doses of TRH. Based on these results, we suggest that TRH has the ability to promote a significant increase in body weight gain in 4-week-old cockerels, and the stimulatory effects may be mediated through GH and/or thyroid hormones.

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“…The demonstration of increased basal GH secretion in chicks when endogenous TRH levels would be expected to be high [12,35] and a suppression of basal GH secretion following the administration of TRH antiserum [H. Klandorf, S. Harvey and H. Fraser, unpub lished observations] suggest a physiological role for TRH in the regulation of avian GH secretion. This possibility is supported by the observation that TRH is effective at phys iological doses [15], at doses less than those required to sti mulate thyroid function [5,17,19,21,22,28], the changes in which are of lesser magnitude than the GH responses evoked.…”

Section: Discussionmentioning

confidence: 99%

TRH Stimulation of in vivo GH Release in the Domestic Fowl

Scanes

Harvey

1985

Neuroendocrinology

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Thyrotropin-releasing hormone (TRH) stimulated in vivo growth hormone (GH) release in conscious and anesthetized young domestic fowl. The administration of the presumed metabolites of TRH, deamido-TRH (TRH-OH) and histidyl-proline diketopiperazine (HPD), was followed by small but significant (p < 0.05) increases in the plasma concentrations of GH in both conscious and anesthetized chicks. However, the ability of TRH-OH or HPD to stimulate GH secretion was less than that observed with a 100-fold lower dose of TRH. The administration of either TRH-OH or HPD with TRH increased the GH response over that observed with TRH alone. The ability of chicken plasma to degrade exogenous TRH in vitro was determined by measuring immunoreactive TRH (IR-TRH) content and by assessing the ability of the incubated samples to increase the plasma concentration of GH when administered to young fowl. The in vitro half-life of TRH was estimated to be 9.8 (by immunoassay) and 9.6 (by a biological index) min for plasma from adult male chickens and 23.9 (by immunoassay) and 20.2 (by biological index) min for plasma from 6-week-old chicks. This difference in degradation may account, at least in part, for the observed age-related decrease in the plasma concentration of GH in birds and for the diminished GH responsiveness of adult birds to exogenous TRH.

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Growth hormone and proclatin in avian species

Cited by 49 publications

References 47 publications

Does prolactin mediate parental and life-history decisions in response to environmental conditions in birds? A review

Does prolactin mediate parental and life-history decisions in response to environmental conditions in birds? A review

Thyrotropin-Releasing Hormone Stimulates Body Weight Gain and Increases Thyroid Hormones and Growth Hormone in Plasma of Cockerels

TRH Stimulation of in vivo GH Release in the Domestic Fowl

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