Flight Effects on Plasma Levels of Lipid, Glucagon and Thyroid Hormones in Homing Pigeons

George, J. C.; John, T. M.; Mitchell, M.A.

doi:10.1055/s-2007-1009283

Cited by 21 publications

(10 citation statements)

References 15 publications

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“…Glucagon. Plasma glucagon concentration was measured by radio immunoassay (Linco Research), as previously described (4,18). The sensitivity of the assay was 20 pg/ml.…”

Section: Methodsmentioning

confidence: 99%

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Heat stress increases apical glucose transport in the chicken jejunum

Garriga¹,

Hunter²,

Amat³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

175

103

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In chickens, elevated environmental temperature reduces food intake. We have previously reported that, during heat stress, the intestinal mucosa has an increased capacity to take up sugars. To investigate whether the effects of warm environment on sugar uptake are an intestinal adaptation to lower energy intake or a response attributable to heat stress, we examined the glucose transport kinetics of apical and basolateral membranes of the jejunum and the mucosal morphology of broiler chickens maintained in climatic chambers for 2 wk. Experimental groups were 1) control ad libitum (CAL), fed ad libitum and in thermoneutral conditions (20 degrees C); 2) heat stress ad libitum (HSAL), fed ad libitum and kept in a heated environment (30 degrees C); and 3) control pair-fed (CPF), maintained in thermoneutral conditions and fed the same amount of food as that consumed by the HSAL group. Both the CPF and the HSAL groups showed reduced body weight gain, but only the HSAL chickens had lower plasma thyroid hormones and higher corticosterone than CAL and CPF groups. The fresh weight and length of the jejunum were only reduced in the HSAL group. The activity and expression of apical sodium-dependent glucose transporter 1 (SGLT-1) were increased by approximately 50% in the HSAL chickens, without effects in the CPF group. No changes in K(d) or in SGLT-1 and glucose transporter-2 K(m) were observed in the pair-fed and heated birds. These results support the view that increased intestinal hexose transport capacity is entirely dependent on adaptations of apical SGLT-1 expression to heat stress and is not due to reduced food intake.

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“…Glucagon. Plasma glucagon concentration was measured by radio immunoassay (Linco Research), as previously described (4,18). The sensitivity of the assay was 20 pg/ml.…”

Section: Methodsmentioning

confidence: 99%

“…The sensitivity of the assay was 20 pg/ml. Because the primary antibody is directed at a mammalian glucagon molecule, the values are expressed as glucagon-like immunoreactivity for avian plasma, as previously described (4,18).…”

Section: Methodsmentioning

confidence: 99%

Heat stress increases apical glucose transport in the chicken jejunum

Garriga¹,

Hunter²,

Amat³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

175

103

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show abstract

“…It is now well established that during sus tained muscular activity, birds metabolize fat as the chief fuel [49][50][51][52][53], Marked increases in postflight plasma levels of triglycerides, free fatty acids (FFA), glucagon and growth hor mone (GH) have been reported in homing pigeons [23,54], Increases in plasma levels of FFA and GH have also been shown in pigeons subjected to heat stress and dehydration [55], The observation that plasma levels of AVT are increased in heat-stressed domestic fowl [ 14] suggests that AVT may have a lipolytic action besides its well-known role as an anti diuretic hormone. That AVT has indeed an adipokinetic action has been demonstrated in pigeon in vivo and also in in vitro experi ments [56] using pigeon adipose tissue slices [57], an action that may be mediated by cAMP [58], In this context, it may be men tioned that the release of AVT from the poste rior lobe in migratory birds prior to migration has been considered as an important event in the initiation of Spring migratory activity [59].…”

Section: Discussionmentioning

confidence: 99%

“…Trained homing pigeons are an excellent experimental material for studies on the ef fects of natural free flight on the physiology of bird flight. Recent studies with homing pi geons have thrown considerable new light on the effects of flight on circulating levels of metabolites and certain hormones involved in metabolic regulation [21][22][23], In the present study, we have investigated possible changes in circulating levels of AVT and MT as a result of flight in homing pigeons.…”

Section: Introductionmentioning

confidence: 99%

Flight Effects on Plasma Levels of Neurohypophysial Hormones in Homing Pigeons

George

John²,

Koike³

1992

Biological Signals

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A significant increase in the circulating levels of arginine vasotocin (AVT), without change in plasma osmolality, was observed in homing pigeons immediately after a flight of 48 km, lasting 60–80 min. This increase in plasma AVT is perceived as part of an overall homeostatic mechanism of mobilizing lipid as fuel for the flight muscles, of water conservation and temperature regulation in the body during the homing flight within the specific distance and duration of flight and under normal weather conditions. However, there was no change in plasma levels of mesotocin (MT) which suggests that the birds were under no significant stress during the flight.

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“…The role of other hormones in the regulation of flight metabolism has been investigated in free-flying homing pigeons but not in migrant birds. After a flight of 48 km or about 1.5 h, significant increases of glucagon, adrenaline, noradrenaline, and growth hormone and either significantly reduced or unchanged concentrations of T3 and T4 were found (George et al 1989;John et al 1988;Viswanathan et al 1987). George et al (1989) concluded that increased sympathetic activity increases glucagon, a lipid-mobilizing hormone.…”

Section: Hormonal Regulation Of Flight Metabolismmentioning

confidence: 96%

Physiological Aeroecology: Anatomical and Physiological Adaptations for Flight

Jenni-Eiermann

Srygley

2017

Aeroecology

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Flight has evolved independently in birds, bats, and insects and was present in the Mesozoic pterosaurians that have disappeared. Of the roughly one million living animal species, more than three-quarters are flying insects. Flying is an extremely successful way of locomotion. At first glance, this seems surprising because leaving the ground and moving in the air is energetically expensive. We will therefore start with the question: why do some animals spend a substantial proportion of their life in the air? To generate lift, a few key features are required, and yet, animals show incredible diversity in their flight mechanics. We will review constraints imposed by body size including anatomical adaptations of the skeleton, muscles, and organs necessary to stay airborne with a special focus on the wings. Ecology of the aerial organism, such as diet or migration, has diversified flight styles and the physiological adaptations required to optimize performance. For example, animals are exposed to low temperatures and low oxygen pressure at high altitude, whereas overheating can pose a problem at low altitudes. Moreover, aerial prey can be particularly apparent to aerial predators resulting in selection on flight speed and maneuverability of predators and prey. Flight is energetically costly, much more costly than walking, with the majority of the cost dictated by body mass. Hence, adding weight load to fuel flight also adds to the cost of flight. We review energy supply

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Flight Effects on Plasma Levels of Lipid, Glucagon and Thyroid Hormones in Homing Pigeons

Cited by 21 publications

References 15 publications

Heat stress increases apical glucose transport in the chicken jejunum

Heat stress increases apical glucose transport in the chicken jejunum

Flight Effects on Plasma Levels of Neurohypophysial Hormones in Homing Pigeons

Physiological Aeroecology: Anatomical and Physiological Adaptations for Flight

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