Thyroid and gonad in the oxidative metabolism, erythropoiesis, and light response of the migratory redheaded bunting, Emberiza bruniceps

Thapliyal, J. P.; Lal, P.; Pati, Atanu Kumar; Gupta, B. B. P.

doi:10.1016/0016-6480(83)90061-8

Cited by 21 publications

(5 citation statements)

References 40 publications

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“…However, when he replaced T in castrated Bramblings, he found no change in their rate of metabolism. Similar declines in post-castration metabolic rate have been reported for Japanese Quail Coturnix coturnix japonica (Hänssler and Prinzinger 1979), Redheaded Buntings Emberiza bruniceps (Thapliyal et al 1983) and Spotted Munia Lonchura punctulata (Gupta and Thapliyal 1984) with subsequent T treatment failing to restore metabolic rate in each of these species.…”

Section: Basal Metabolic Ratesupporting

confidence: 72%

Testosterone does not affect basal metabolic rate or blood parasite load in captive male White‐plumed Honeyeaters Lichenostomus penicillatus

Buttemer¹,

Astheimer²

2000

Journal of Avian Biology

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2000. Testosterone does not affect basal metabolic rate or blood parasite load in captive male White-plumed Honeyeaters Lichenostomus penicillatus. -J. Avian Biol. 31: 479-488.We examined physiological and morphological responses of reproductively active male White-plumed Honeyeaters Lichenostomus penicillatus to exogenous testosterone (T). Birds used in the experiment were held in captivity for two weeks and then were given subcutaneous implants which were either empty (controls) or T-filled silastic capsules (T-treated). Basal metabolic rates (BMR) measured just prior to implantation and again four weeks later were not affected by treatment and were indistinguishable from BMR measured in free-living White-plumed Honeyeaters, averaging 3.2 ml O 2 /g/h. Plasma T levels measured at the time of the final BMR evaluation were 1.2, 1.8, and 5.5 ng/ml in free-living, control, and T-treated birds, respectively. Body mass was unaffected by T treatment. All captive birds used in the experiment displayed Haemoproteus sp. infection, but blood parasite loads did not differ temporally between T-treated and control birds during their 6-week captivity. Corticosterone secretion during a 60-min capture-handling protocol did not differ between control and T-treated birds, but corticosterone levels at each sampling period in captive birds were significantly lower than those of free-living males. Three morphological variables of White-plumed Honeyeaters were affected by T treatment: T-treated birds had significantly higher haematocrits and larger testes than control birds and also showed no change in bill colour. Control birds, by contrast, showed substantial lightening of the proximal half of their bills. We conclude that BMR, resistance to Haemoproteus infection, and stress responsiveness are not directly affected by T levels in male White-plumed Honeyeaters.

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Section: Basal Metabolic Ratesupporting

confidence: 72%

Testosterone does not affect basal metabolic rate or blood parasite load in captive male White‐plumed Honeyeaters Lichenostomus penicillatus

Buttemer¹,

Astheimer²

2000

Journal of Avian Biology

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“…Higher hematocrit in males has often been reported in avian bibliography (review in Sturkie 1986), probably being explained by differences in endocrine profiles. Thus, males have higher androgen levels, which are associated with increased erythropoiesis, whereas females have higher estrogen concentrations, which are related to lower erythropoiesis (e.g., Thapliyal et al 1983;Mooradian et al 1987). However, in contrast to the findings of Negro et al (2001), we failed to find significant differences in plasma carotenoids between males and females in this species, which may be attributed to the relatively low number of birds sampled.…”

Section: Discussioncontrasting

confidence: 96%

Repeated Sampling but Not Sampling Hour Affects Plasma Carotenoid Levels

Pérez‐Rodríguez

Alonso‐Álvarez

Viñuela

2007

Physiological and Biochemical Zoology

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Carotenoid pigments have become a central subject of research on animal signaling systems during the past decade. Thus, measurement of plasma carotenoid levels is widespread in the literature. Many plasma biochemical parameters tend to vary with the hour of sampling, which may be an important source of sampling error. However, little is known about this kind of variation for circulating carotenoids. With a sampling protocol that allowed us to separately analyze the effect of sampling hour and repeated blood extraction at the within-individual level, we evaluated the effect of these two parameters on plasma carotenoid concentration in captive red-legged partridges (Alectoris rufa). The hour of sampling did not show a significant influence on carotenoid variability. Nevertheless, carotenoid levels significantly decreased as a result of repeated sampling. In fact, carotenoid variability was positively related to hematocrit values, which also decreased throughout the experiment. Furthermore, the effect was evident from the second sampling event. These results suggest that blood samples for carotenoid analysis may be obtained at random during the daytime with no serious risk of adding variance to data obtained. However, the effect of hemodilution associated with repeated blood extraction should be carefully considered in those studies involving repeated sampling.

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“…The energetic cost of producing such small quantities of T are quite low, particularly when compared with peak levels measured during the breeding season (usually 25 times as high). Also, T injections in castrated Japanese quail Coturnix coturnix (HANSSLER & PRINZINGER 1979) and red-headed buntings Emberizu bruniceps (THAPLIYAL et al 1983) failed to increase oxygen consumption. Hence, any costs associated with a higher level of T may be due to its resulting effects on increased aggressiveness.…”

Section: Discussionmentioning

confidence: 98%

Social Status and Circulating Levels of Hormones in Flocks of House Sparrows, Passer domesticus

Hegner

Wingfield

1987

Ethology

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Captive groups of house sparrows Passer domesticus formed stable social hierarchies during a two-week test period. Higher-ranking individuals were more aggressive during the first week of testing and had higher plasma levels of luteinizing hormone (LH) and testosterone (T) at the end of that week. Higher-ranking individuals continued to be more aggressive during the second week of testing, but concentrations of L H and T in blood no longer were related to social status. Higherranking individuals also did not have higher levels of these hormones on the day the tournament began. Circulating titers of dihydrotestosterone and corticosterone were random with respect to social status. These results support the hypothesis that social rank and aggressiveness are related to circulating levels of T, but this relationship is expressed only when social status is being established or is actively 'challenged'.

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Thyroid and gonad in the oxidative metabolism, erythropoiesis, and light response of the migratory redheaded bunting, Emberiza bruniceps

Cited by 21 publications

References 40 publications

Testosterone does not affect basal metabolic rate or blood parasite load in captive male White‐plumed Honeyeaters Lichenostomus penicillatus

Testosterone does not affect basal metabolic rate or blood parasite load in captive male White‐plumed Honeyeaters Lichenostomus penicillatus

Repeated Sampling but Not Sampling Hour Affects Plasma Carotenoid Levels

Social Status and Circulating Levels of Hormones in Flocks of House Sparrows, Passer domesticus

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