scholarly journals Gonadotropin-inhibitory hormone in Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii): cDNA identification, transcript localization and functional effects in laboratory and field experiments

2004 ◽  
Vol 182 (1) ◽  
pp. 33-42 ◽  
Author(s):  
T Osugi ◽  
K Ukena ◽  
GE Bentley ◽  
S O'Brien ◽  
IT Moore ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cellular Localization ◽  
Field Experiments ◽  
Bird Species ◽  
Free Living ◽  
Zonotrichia Leucophrys ◽  
Gonadotropin Release ◽  
Zonotrichia Leucophrys Gambelii ◽  
Gonadotropin Inhibitory Hormone ◽  
Seasonally Breeding

The neuropeptide control of gonadotropin secretion is primarily through the stimulatory action of the hypothalamic decapeptide, GnRH. We recently identified a novel hypothalamic dodecapeptide with a C-terminal LeuPro-Leu-Arg-Phe-NH2 sequence in the domestic bird, Japanese quail (Coturnix japonica). This novel peptide inhibited gonadotropin release in vitro from the quail anterior pituitary; thus it was named gonadotropin-inhibitory hormone (GnIH). GnIH may be an important factor regulating reproductive activity not only in domesticated birds but also in wild, seasonally breeding birds. Thus, we tested synthetic quail GnIH in seasonally breeding wild bird species. In an in vivo experiment, chicken gonadotropin-releasing hormone-I (cGnRH-I) alone or a cGnRH-I/quail GnIH cocktail was injected i.v. into non-breeding song sparrows (Melospiza melodia). Quail GnIH rapidly (within 2 min) attenuated the GnRH-induced rise in plasma LH. Furthermore, we tested the effects of quail GnIH in castrated, photostimulated Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii), using quail GnIH or saline for injection. Again, quail GnIH rapidly reduced plasma LH (within 3 min) compared with controls. To characterize fully the action of GnIH in wild birds, the identification of their endogenous GnIH is essential. Therefore, in the present study a cDNA encoding GnIH in the brain of Gambel's white-crowned sparrow was cloned by a combination of 3' and 5' rapid amplification of cDNA ends and compared with the quail GnIH cDNA previously identified. The deduced sparrow GnIH precursor consisted of 173 amino acid residues, encoding one sparrow GnIH and two sparrow GnIH-related peptides (sparrow GnIH-RP-1 and GnIH-RP-2) that included Leu-Pro-Xaa-Arg-Phe-NH2 (Xaa=Leu or Gln) at their C-termini. All these peptide sequences were flanked by a glycine C-terminal amidation signal and a single basic amino acid on each end as an endoproteolytic site. Although the homology of sparrow and quail GnIH precursors was approximately 66%, the C-terminal structures of GnIH, GnIH-RP-1 and GnIH-RP-2 were all identical in two species. In situ hybridization revealed the cellular localization of sparrow GnIH mRNA in the paraventricular nucleus (PVN) of the hypothalamus. Immunohistochemical analysis also showed that sparrow GnIH-like immunoreactive cell bodies and terminals were localized in the PVN and median eminence respectively. Thus, only the sparrow PVN expresses GnIH, which appears to be a hypothalamic inhibitory factor for LH release, as evident from our field injections of GnIH into free-living breeding white-crowned sparrows. Sparrow GnIH rapidly (within 2 min) reduced plasma LH when injected into free-living Gambel's white-crowned sparrows on their breeding grounds in northern Alaska. Taken together, our results indicate that, despite amino acid sequence differences, quail GnIH and sparrow GnIH have similar inhibitory effects on the reproductive axis in wild sparrow species. Thus, GnIH appears to be a modulator of gonadotropin release.

scholarly journals Corticosterone Responses in Wild Birds: The Importance of Rapid Initial Sampling

The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 129-135 ◽  
Author(s):  
L. Michael Romero ◽  
Robin C. Romero
Keyword(s):  
Stress Responses ◽  
Passer Domesticus ◽  
Free Living ◽  
House Sparrows ◽  
Zonotrichia Leucophrys ◽  
Elapsed Time ◽  
Corticosterone Response ◽  
Calcarius Lapponicus ◽  
Initial Sampling ◽  
Zonotrichia Leucophrys Gambelii

Abstract Corticosterone concentrations in birds usually rise in response to capture and handling, and it is often assumed that this change is predictable. We tested this assumption by leaving Gambel's White-crowned Sparrows (Zonotrichia leucophrys gambelii), House Sparrows (Passer domesticus), and Lapland Longspurs (Calcarius lapponicus) in nets or traps for 15 min following capture and comparing their corticosterone response over the next 60 min with birds removed immediately. White-crowned Sparrows and House Sparrows left in mist nets for 15 min and then bled had significantly elevated corticosterone concentrations compared to controls that were immediately removed from the net and bled. Corticosterone concentrations over the next 45 min of handling and restraint were similar between groups. In another experiment, White-crowned Sparrows and Lapland Longspurs were captured using seed-baited Potter traps. The corticosterone response of White-crowned Sparrows left in the trap for 15 min did not differ from White-crowned Sparrows removed immediately. Leaving Lapland Longspurs in the trap had no effect in the initial 10 min of handling and restraint, but at 30 and 60 min these birds had significantly lower corticosterone concentrations than longspurs removed immediately from the trap. These data indicate that failing to immediately remove birds from nets or traps can alter the corticosterone response to subsequent stressful stimuli in unpredictable ways. This result emphasizes that the elapsed time from capture is a critical variable in assessing stress responses in free-living birds. Respuestas de los Niveles de Corticosterona en Aves Silvestres: La Importancia de un Muestreo Inicial Inmediato Resumen. Las concentraciones de corticosterona en las aves usualmente aumentan en respuesta a la captura y manipulación, y muchas veces se supone que estos cambios son predecibles. Pusimos a prueba esta suposición reteniendo individuos de las especies Zonotrichia leucophrys gambelii, Passer domesticus y Calcarius lapponicus en redes o trampas durante los 15 minutos subsecuentes a la captura y comparamos sus respuestas en los niveles de corticosterona durante los siguientes 60 minutos con las de individuos removidos inmediatamente de las trampas y redes. Las muestras de sangre de Z. l. gambelii y P. domesticus que fueron obtenidas después de 15 minutos de retención en las redes tuvieron niveles de corticosterona significativamente más altos que las de los individuos control obtenidas inmediatamente después de la captura. Durante los 45 minutos siguientes de manipulación y captura, las concentraciones de corticosterona fueron similares entre los dos grupos. En otro experimento, Z. l. gambelii y C. lapponicus fueron capturados mediante trampas “Potter” cebadas con semillas. La respuesta en los niveles de corticosterona de Z. l. gambelii no fue diferente entre individuos retenidos en las trampas por 15 minutos e individuos removidos inmediatamente. Para individuos de C. lapponicus retenidos en las trampas no hubo un efecto durante los 10 minutos iniciales de manipulación y captura, pero a los 30 y 60 minutos estas aves tuvieron concentraciones significativamente menores que los individuos removidos inmediatamente. Estos resultados indican que al no remover inmediatamente a las aves de las redes o trampas, las respuestas en los niveles de corticosterona a estímulos estresantes pueden verse alteradas de una manera impredecible. Estos resultados enfatizan que en aves silvestres, el lapso de tiempo desde la captura es una variable crítica en la determinación de las respuestas al estrés.

Migratory behaviour of captive white-crowned sparrows, Zonotrichia leucophrys gambelii, differs during autumn and spring migration

Behaviour ◽  
2006 ◽  
Vol 143 (10) ◽  
pp. 1219-1240 ◽  
Author(s):  
Marilyn Ramenofsky ◽  
Renée Agatsuma
Keyword(s):  
Life History ◽  
High Intensity ◽  
Primary Source ◽  
Migratory Restlessness ◽  
Long Distance ◽  
Free Living ◽  
Zonotrichia Leucophrys ◽  
Life History Stages ◽  
In Captivity ◽  
Zonotrichia Leucophrys Gambelii

AbstractGambel's white-crown sparrow (Zonotorichia leucophrys gambelii) is a long-distance, over-land migrant. In captivity birds display many characteristics of the autumn and spring migratory life history stages that include hyperphagia, fattening and high intensity nocturnal activity termed migratory restlessness or Zugunruhe. We recorded the behaviour of captive birds while simultaneously collecting 24 h locomotor activity. These data were used to define the behaviour displayed by captive birds during autumn and spring in order to compare the two migratory stages and to draw inferences for free-living birds. The predominant behaviour during day and nighttime was rest. Feeding occurred only during daylight hours but at a greater frequency in autumn than spring. Birds generally used their feet as the primary source of locomotion during the day termed 'jump'. During the night, two distinct behaviours, 'beak-up flight' and 'beak-up' involving high intensity wing motions were observed and considered components of migratory restlessness. The frequency of the 'beak-up flight' was greatest during spring and associated with the enhanced tempo of vernal migration. In both stages, migratory restlessness was preceded by a quiescent phase, the occurrence of which differed and related to time available for foraging and length of the night. Given these findings, we hypothesize that diel behaviours displayed by autumn and spring migrants in captivity highlight distinctions between the two life history stages.

Protein intake and the dynamics of the postnuptial molt in White-crowned Sparrows, Zonotrichia leucophrys gambelii

1991 ◽  
Vol 69 (8) ◽  
pp. 2225-2229 ◽  
Author(s):  
Mary E. Murphy ◽  
James R. King
Keyword(s):  
Body Mass ◽  
Sulfur Amino Acids ◽  
Daily Consumption ◽  
Free Living ◽  
Zonotrichia Leucophrys ◽  
High Quality Protein ◽  
Protein Group ◽  
The Mean ◽  
Zonotrichia Leucophrys Gambelii

Nutritional constraints have often been invoked as either ultimate or proximate agents that account for variation in the schedule and intensity of molt and the quality of the new plumage. We examined this hypothesis by analyzing the dynamics of postnuptial molt and the condition of the new feathers in seven groups of White-crowned Sparrows (Zonotrichia leucophrys gambelii) in which the mean daily consumption of high-quality protein in otherwise balanced diets ranged from subadequate (0.20 g/bird) to superadequate (3.23 g/bird). Mean body mass during molt did not differ among the six groups consuming 0.46 g/bird-day or more (0.69, 0.97, 1.76, 1.99, and 3.23 g/bird-day) but was significantly less throughout molt (e.g., ca. 20 vs. 26 g in mid to late molt) in the group subsisting on 0.20 g/bird-day. The mean date of molt onset (27 June – 2 July) was statistically the same in all the groups, as was the duration of molt (51–57 days) in the six groups consuming 0.46 g or more of protein per day. In the lowest-protein group (0.20 g/bird-day) the molt lasted > 111 days. The protraction of molt resulted from both a slower growth rate of flight feathers and longer shedding intervals between them. The new primary remiges of the birds in this group averaged 4–9% shorter than in the six other groups, which were statistically indistinguishable from each other. These results are consistent with those of earlier experiments on the effects on molt of shortages of nutritionally balanced diets and of diets deficient only in sulfur amino acids. Molt is very resistant to the kinds of malnutrition that free-living birds may encounter. Only very severe levels of privation that sharply depress body mass and potentially threaten life significantly slow the rate of molt or reduce the quality of plumage.

Experiments on the Control of Deceptive Signals of Status in White-Crowned Sparrows

The Auk ◽  
1987 ◽  
Vol 104 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Gary N. Fugle ◽  
Stephen I. Rothstein
Keyword(s):  
Field Experiments ◽  
Adult Males ◽  
Zonotrichia Leucophrys ◽  
Status Signaling ◽  
Dominance Interactions ◽  
The Social ◽  
Zonotrichia Leucophrys Gambelii ◽  
The Stability ◽  
Control Hypothesis ◽  
And Control

Abstract We showed previously that crown plumage brightness signals relative dominance ability in White-crowned Sparrows (Zonotrichia leucophrys gambelii). We now test the social-control hypothesis for the evolutionary stability of status signaling against invasion by individuals with brighter crowns than justified by their intrinsic dominance ability. "Cheating" immature females, with crowns painted to resemble bright adult males, and "control" immature females, with crowns painted a typical immature appearance or left unpainted, were released into two separate wild sparrow flocks and into two different captive groups that contained birds of all age and sex classes. In the field experiments, cheaters were more successful than controls in dominance interactions with other immatures; both groups were equally unsuccessful against adults. In the captivity experiments, cheaters generally dominated controls and were more successful than they in interactions with immature males and adult females but not with adult males. Cheaters did not receive more aggression from dominant individuals than did controls in any experiment, and in two experiments they received significantly less aggression. Thus, we found no socially mediated costs for sparrows with deceptive signals. Instead, we showed that immature females that cheat can benefit. The stability of the White-crowned Sparrow signaling system remains unexplained. We discuss the potential influence of predators on individual plumage differences and offer additional hypotheses for the control of deceptive signals.

Malnutrition during the postnuptial molt of White-crowned Sparrows: feather growth and quality

1988 ◽  
Vol 66 (6) ◽  
pp. 1403-1413 ◽  
Author(s):  
Mary E. Murphy ◽  
James R. King ◽  
Jianjian Lu
Keyword(s):  
Control Group ◽  
Free Living ◽  
Zonotrichia Leucophrys ◽  
Balanced Diet ◽  
Feather Growth ◽  
Ad Libitum ◽  
Zonotrichia Leucophrys Gambelii ◽  
The Times ◽  
Ad Libitum Intake ◽  
Time Required

It has often been alleged that avian molt can be interrupted or delayed by food deprivation or malnutrition. We examined this experimentally in captive White-crowned Sparrows (Zonotrichia leucophrys gambelii). Beginning either at the natural onset of postnuptial molt or 1 month before its onset, groups of birds were fed either inadequate amounts of a balanced diet (60 or 80% of the ad libitum intake of a control group) or unlimited amounts of a diet deficient only in cyst(e)ine and methionine. Except in the 60% premolt group, the malnourished birds did not postpone or interrupt molt in spite of losses ranging from 20 to 38% of initial body mass. Molt was significantly protracted in all except the 60% premolt group as a result of both increased shedding interval and decreased feather growth rates. Their new plumage weighed less than that of control birds, and their remiges were slightly shorter and often deformed or achromatic. The occurrence of fault bars corresponded to the times when the birds were handled, but was not correlated with other plumage defects. Surviving birds of the 60% premolt group did not molt until allowed to feed ad libitum, but then produced a normal plumage in about two-thirds of the time required by the controls. To summarize, molt is a very conservative aspect of self maintenance that is distorted only by planes of malnutrition that free-living sparrows either do not encounter during the summer or do not survive.

Characterization of a cDNA encoding a novel avian hypothalamic neuropeptide exerting an inhibitory effect on gonadotropin release

2001 ◽  
Vol 354 (2) ◽  
pp. 379-385 ◽  
Author(s):  
Honoo SATAKE ◽  
Miki HISADA ◽  
Tsuyoshi KAWADA ◽  
Hiroyuki MINAKATA ◽  
Kazuyoshi UKENA ◽  
...  
Keyword(s):  
Amino Acid ◽  
Basic Amino Acid ◽  
Inhibitory Effect ◽  
Gene Encoding ◽  
Specific Expression ◽  
Gonadotropin Secretion ◽  
Putative Gene ◽  
Gonadotropin Release ◽  
Pcr Products ◽  
Gonadotropin Inhibitory Hormone

We previously isolated a novel dodecapeptide containing a C-terminal -Arg-Phe-NH2 sequence, SIKPSAYLPLRF-NH2 (RFamide peptide), from the quail brain. This quail RFamide peptide was shown to decrease gonadotropin release from the cultured anterior pituitary and to be located at least in the quail hypothalamo-hypophysial system. We therefore designated this RFamide peptide gonadotropin inhibitory hormone (GnIH). In the present study we characterized the GnIH cDNA from the quail brain by a combination of 3′ and 5′ rapid amplification of cDNA ends (‘RACE’). The deduced GnIH precursor consisted of 173 amino acid residues, encoding one GnIH and two putative gene-related peptide (GnIH-RP-1 and GnIH-RP-2) sequences that included -LPXRF (X = L or Q) at their C-termini. All these peptide sequences were flanked by a glycine C-terminal amidation signal and a single basic amino acid on each end as an endoproteolytic site. Southern blotting analysis of reverse-transcriptase-mediated PCR products demonstrated a specific expression of the gene encoding GnIH in the diencephalon including the hypothalamus. Furthermore, mass spectrometric analyses detected the mass numbers for matured GnIH and GnIH-RP-2, revealing that both peptides are produced from the precursor in the diencephalon as an endogenous ligand. Taken together, these results lead to the conclusion that GnIH is a hypothalamic factor responsible for the negative regulation of gonadotropin secretion. Furthermore, the presence of a novel RFamide peptide family containing a C-terminal -LPXRF-NH2 sequence has been revealed.

The protein requirement for maintenance in the White-crowned Sparrow, Zonotrichia leucophrys gambelii

1993 ◽  
Vol 71 (10) ◽  
pp. 2111-2120 ◽  
Author(s):  
Mary E. Murphy
Keyword(s):  
Amino Acid ◽  
Body Mass ◽  
Dietary Protein ◽  
Wild Birds ◽  
N Balance ◽  
N Loss ◽  
Protein Requirement ◽  
Zonotrichia Leucophrys ◽  
Protein Requirements ◽  
Zonotrichia Leucophrys Gambelii

Assumptions about potential mismatches between protein demand and protein availability are implicit in many hypotheses pertaining to the ecology of wild birds. However, few direct measures of the protein requirements of wild birds have been made. I evaluated the requirement for protein for maintenance of a wild granivorous passerine, the White-crowned Sparrow (Zonotrichia leucophrys gambelii). I estimated protein requirement from measures of endogenous nitrogen (N) loss, N balance, and changes in body mass in wintering adult birds. The experimental birds were kept indoors at 23 °C (8.5 h light: 15.5 h dark) and fed semisynthetic diets that differed only in their concentrations of protein (0–17.3%) and starch, which were reciprocally adjusted. The amino acid profiles of the protein in the diets were identical and were formulated to match the average amino acid profile of the mixed proteins of a diet containing grains, seeds, insects, and fruits. In White-crowned Sparrows, the protein requirements for maintenance of body mass (366 mg/d) and a positive N balance equal to that of birds ingesting the acclimation diets (436 mg/d) were 7.3 and 8.7% protein, respectively, in a diet containing 12.4 kJ apparent metabolizable energy per gram dry mass. The estimated minimum maintenance requirement for protein for N equilibrium, derived from regressing N excretion on N intake, equalled 264 mg protein/d, or ca. 5.3% dietary protein. Measures of endogenous N loss (endogenous urinary N loss plus metabolic fecal N loss) equalled 14.7 mg N/d, indicating that White-crowned Sparrows need to replace at least 92 mg body protein/d. Dietary protein content had little influence on the birds' utilization of dietary energy and daily metabolized energy. The apparent contradiction in the requirement for a positive N balance to maintain body mass is discussed.

scholarly journals Developmental changes in gonadotropin-inhibitory hormone in the Japanese quail (Coturnix japonica) hypothalamo-hypophysial system

2003 ◽  
Vol 178 (2) ◽  
pp. 311-318 ◽  
Author(s):  
T Ubuka ◽  
M Ueno ◽  
K Ukena ◽  
K Tsutsui
Keyword(s):  
Japanese Quail ◽  
Median Eminence ◽  
Anterior Pituitary ◽  
Coturnix Japonica ◽  
Developmental Changes ◽  
External Layer ◽  
Mature Peptide ◽  
Gonadotropin Release ◽  
Gonadotropin Inhibitory Hormone ◽  
Precursor Mrna

We previously isolated a novel dodecapeptide containing a C-terminal -Arg-Phe-NH(2) sequence, SIKPSAYLPLRF-NH(2) (RFamide peptide), from the Japanese quail (Coturnix japonica) brain. This novel quail peptide was shown to be located in neurons of the paraventricular nucleus (PVN) and their terminals in the median eminence (ME), and to decrease gonadotropin release from cultured anterior pituitary in adult birds. We therefore designated this peptide gonadotropin-inhibitory hormone (GnIH). Furthermore, a cDNA encoding the GnIH precursor polypeptide has been characterized. To understand the physiological roles of this peptide, in the present study we analyzed developmental changes in the expressions of GnIH precursor mRNA and the mature peptide GnIH during embryonic and posthatch ages in the quail diencephalon including the PVN and ME. GnIH precursor mRNA was expressed in the diencephalon on embryonic day 10 (E10) and showed a significant increase on E17, just before hatch. GnIH was also detected in the diencephalon on E10 and increased significantly around hatch. Subsequently, the diencephalic GnIH content decreased temporarily, and again increased progressively until adulthood. GnIH-like immunoreactive (GnIH-ir) neurons were localized in the PVN on E10, but GnIH-ir fibers did not extend to the ME. However, GnIH-ir neurons increased in the PVN on E17, just before hatch, and GnIH-ir fibers extended to the external layer of the ME, as in adulthood. These results suggest that GnIH begins its function around hatch and acts as a hypothalamic factor to regulate gonadotropin release in the bird.

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