Central administration of alpha-melanocyte-stimulating hormone changes lipid metabolism in chicks

Tachibana, Tetsuya; Oikawa, Daichi; Adachi, Nami; Boswell, Tim; Furuse, Mitsuhiro

doi:10.1016/j.cbpa.2007.05.023

Cited by 16 publications

(5 citation statements)

References 20 publications

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“…Interestingly, birds treated with both diquat and a-MSH did not show such a decline. In this case, the absence of an effect could be associated with changes in lipid metabolism, as a-MSH levels have been positively related to plasma fatty acid levels in birds (Tachibana et al 2007).…”

Section: Discussionmentioning

confidence: 96%

“…Ohtsuka et al 1994;Luperchio et al 1996;Zhang et al 1999), a-MSH affects melanization levels by specifically activating the MC1R, which subsequently enhances the activity of tyrosinase (Ozeki et al 1997;Boswell & Takeuchi 2005). The lack of influence of a-MSH on oxidative stress markers is supported by findings showing that, in contrast to mammals, a-MSH does not enhance heat production in birds (Tachibana et al 2007), which in turn is associated with oxidative stress (e.g. Feder & Hofmann 1999).…”

Section: Discussionmentioning

confidence: 98%

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The expression of melanin-based plumage is separately modulated by exogenous oxidative stress and a melanocortin

2009

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Melanin-based traits involved in animal communication have been traditionally viewed as occurring under strict genetic control. However, it is generally accepted that both genetic and environmental factors influence melanin production. Medical studies suggest that, among environmental factors influencing melanization, oxidative stress could play a relevant role. On the other hand, genetic control would be exerted by the melanocortin system, and particularly by the alpha-melanocyte-stimulating hormone (a-MSH), which triggers the production of eumelanins (black pigments). To determine how the melanocortin system and an exogenous source of oxidative stress interact in the expression of melanin-based plumage, developing red-legged partridges (Alectoris rufa) were manipulated. Some partridges were injected with a-MSH, while other birds received a pro-oxidant molecule (diquat) in drinking water. Controls and birds receiving both treatments were also studied. Both a-MSH-and diquat-treated individuals presented larger eumelanin-based traits than controls, but a-MSHþdiquat-treated birds showed the largest traits, suggesting that oxidative stress and melanocortins promote additive but independent effects. Diquat also induced a decline in the level of a key intracellular antioxidant (glutathione), which is associated with high expression of eumelanin-based signals in other bird species. Some scenarios for the evolution of melanin-based traits in relation to oxidative stress are proposed.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 98%

The expression of melanin-based plumage is separately modulated by exogenous oxidative stress and a melanocortin

2009

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“…Evans Blue saline solution was used for the control group, as in previous studies (Tachibana et al. , ; Bahry et al. ).…”

Section: Methodsmentioning

confidence: 99%

“…Porcine NPY showed a similar affinity to chicken NPYSRs-Y1, -Y4, and -Y5 (Lundell, 2002), so we used it in this study. Evans Blue saline solution was used for the control group, as in previous studies (Tachibana et al 2006(Tachibana et al , 2007Bahry et al 2017). The NPY, the NPYSR-Y5 antagonist and the saline solutions were kept on ice during the experimental period.…”

Section: Animalsmentioning

confidence: 99%

Central NPY ‐Y5 sub‐receptor partially functions as a mediator of NPY ‐induced hypothermia and affords thermotolerance in heat‐exposed fasted chicks

et al. 2017

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Exposure of chicks to a high ambient temperature (HT) has previously been shown to increase neuropeptide Y (NPY) mRNA expression in the brain. Furthermore, it was found that NPY has anti‐stress functions in heat‐exposed fasted chicks. The aim of the study was to reveal the role of central administration of NPY on thermotolerance ability and the induction of heat‐shock protein (HSP) and NPY sub‐receptors (NPYSRs) in fasted chicks with the contribution of plasma metabolite changes. Six‐ or seven‐day‐old chicks were centrally injected with 0 or 375 pmol of NPY and exposed to either HT (35 ± 1°C) or control thermoneutral temperature (CT: 30 ± 1°C) for 60 min while fasted. NPY reduced body temperature under both CT and HT. NPY enhanced the brain mRNA expression of HSP‐70 and ‐90, as well as of NPYSRs‐Y5, ‐Y6, and ‐Y7, but not ‐Y1, ‐Y2, and ‐Y4, under CT and HT. A coinjection of an NPYSR‐Y5 antagonist (CGP71683) and NPY (375 pmol) attenuated the NPY‐induced hypothermia. Furthermore, central NPY decreased plasma glucose and triacylglycerol under CT and HT and kept plasma corticosterone and epinephrine lower under HT. NPY increased plasma taurine and anserine concentrations. In conclusion, brain NPYSR‐Y5 partially afforded protective thermotolerance in heat‐exposed fasted chicks. The NPY‐mediated reduction in plasma glucose and stress hormone levels and the increase in free amino acids in plasma further suggest that NPY might potentially play a role in minimizing heat stress in fasted chicks.

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“…A recent work indicates that the response to a primary PHA injection mirrors pro-inflamatory potential (Vinkler et al 2010), and some of the expected effects of elevated a-MSH include an increase in the induction of pro-inflamatory mediators, a reduction in the induction of anti-inflamatory mediators, and an increased resistance to oxidative stress (review in Ducrest et al 2008). In birds, a-MSH seems to decrease the respiratory quotient (Tachibana et al 2007), and could thereby reduce energy consumption and associated ROS/ RNS production. If so, elevated a-MSH would reduce oxidative stress (e.g., Costantini 2008; but see Barja 2007;Hulbert et al 2007), hence allowing stronger immune responses, as we found in male partridges.…”

Section: A-melanocyte Stimulating Hormone and Immune Responsivenessmentioning

confidence: 97%

Contrasted effects of an oxidative challenge and α-melanocyte-stimulating hormone on cellular immune responsiveness: an experiment with red-legged partridges Alectoris rufa

2011

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Oxidative stress is increasingly recognized as a key selective force shaping evolutionary trade-offs. One such trade-off involves investing in immunity versus combating oxidative stress. While there is broad evidence that mounting an immune response causes increased oxidative stress, the effect that increased oxidative stress during development has at a later stage on immune responsiveness remains little known. The production of melanin-based coloration in vertebrates is influenced by oxidative stress and by hormones, such as the alpha-melanocyte-stimulating hormone (α-MSH). Oxidative stress could impair immunity, and this might be a cost associated with the production of melanin traits. α-MSH has immunomodulatory effects, with most evidence pointing towards an improvement of immunity (improved pro-inflammatory activity). Here, we investigated the effects of an oxidative challenge (exposure to a pro-oxidant compound, diquat) and of experimentally elevated α-MSH on the cell-mediated immune responses (CMIR) of growing young (1 month old) red-legged partridges Alectoris rufa in captivity. CMIR were assessed in response to primary and secondary challenges with phytohemagglutinin (PHA). We specifically tested whether an oxidative challenge during growth and development had a delayed effect (4 months after exposure) on immunity. We found that the diquat treatment did not affect primary CMIR, but significantly reduced secondary CMIR. Elevated α-MSH increased primary CMIR in males, but not in females. Our experimental results are consistent with a trade-off between investing in activities that generate oxidative stress (e.g., growth, reproduction, production of ornaments) versus investing in immunity, and shed new lights onto the inter-relationships between immunity, oxidative stress and the expression of melanin-based coloration in vertebrates, revealing a novel, delayed physiological cost that can contribute to ensuring honest signaling.

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Central administration of alpha-melanocyte-stimulating hormone changes lipid metabolism in chicks

Cited by 16 publications

References 20 publications

The expression of melanin-based plumage is separately modulated by exogenous oxidative stress and a melanocortin

The expression of melanin-based plumage is separately modulated by exogenous oxidative stress and a melanocortin

Central NPY ‐Y5 sub‐receptor partially functions as a mediator of NPY ‐induced hypothermia and affords thermotolerance in heat‐exposed fasted chicks

Contrasted effects of an oxidative challenge and α-melanocyte-stimulating hormone on cellular immune responsiveness: an experiment with red-legged partridges Alectoris rufa

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