Birds from the temperate and cold zones show annual sexual activity accompanied by gonadal changes and fuctuation in their brain gonadotropin-releasing hormone (GnRH) levels. However, most of the studies were done on captive birds where the constant environment can profoundly modify periodical changes. Therefore our aim was to reveal annual variations of hypothalamic and gonadal changes in male, free-living European starlings (Sturnus vulgaris) captured directly from their natural environment. We analyzed hypothalamic GnRH-I immunoreactivity and testes volume. Four key time points of the active reproductive cycle and the photorefractory phase were studied. GnRH-I immunoreactivity was analyzed in the preoptic area (POA) and the median eminence (ME). Photorefractory birds (August) with regressed gonads had the lowest level of GnRH-I immunoreactivity compared to other birds from the active reproductive phases. These results suggest that parallel with the gonadal volume GnRH-I undergoes seasonal changes in adult male free-living European starlings.
light/dark hours per day
Bentley, G. E., Moore, I. T., Sower, S. A., Wingfield J. C. (2004) Evidence for a novel gonadotropin-releasing hormone in hypothalamic and forebrain areas in songbirds. Brain Behav. Evol. 63, 34–46.
Cho, R. N., Hahn T. R. MacDougall-Shackleton, S. Ball G. F. (1998) Seasonal variation in brain GnRH in free-living breeding and photorefractory house finches (Carpodacus mexicanus). Gen. Comp. Endocrinol. 109, 244–250.
Dawson, A. (2004) Evidence against a period of relative photorefractoriness during the recovery of photosensitivity in common starlings. Gen. Comp. Endocrinol. 136, 117–121.
Dawson, A., Follett, B. K., Goldsmith, A. R., Nicholls T. J. (1987) Hypothalamic gonadotrophin-re-leasing hormone and pituitary and plasma FSH and prolactin during photostimulation and photorefractoriness in intact and thyroidectomized starlings (Sturnus vulgaris). J. Endocrinol. 115, 211–220.
Dawson, A., Goldsmith A. R. (1983) Plasma prolactin and gonadotrophins during gonadal development and the onset of photorefractoriness in male and female starlings (Sturnus vulgaris) on artificial photoperiods. J. Endocrinol. 97, 253–260.
Dawson, A., Goldsmith A. R. (1997) Changes in gonadotrophin-releasing hormone (GnRH-I) in the pre-optic area and median eminence of starlings (Sturnus vulgaris) during the recovery of photosensitivity and during photostimulation. J. Reprod. Fertil. 111, 1–6.
Dittami, J., Gwinner, E., Follett, B. K., Prossinger, H. (2005) Changes in circadian LH-secretion patterns and annual gonadal cycles in the male European starling (Sturnus vulgaris). J. Ornithol. 146, 338–347.
Follett, B. K., Maung S. L. (1978) Rate of testicular maturation, in relation to gonadotrophin and testosterone levels, in quail exposed to various artificial photoperiods and to natural day lengths. J. Endocrinol. 78, 267–280.
Foster, R. G., Panzica, G. C., Parry, D. M., Viglietti-Panzica, C. (1988) Immunocytochemical studies on the LHRH system of the Japanese quail: inluence by photoperiod and aspects of sexual differentiation. Cell Tissue Res. 253, 327–335.
Foster, R. G., Plowman, G., Goldsmith, A. R., Follett B. K. (1987) Immunohistochemical demonstration of marked changes in the LHRH system of photosensitive and photorefractory European starlings (Sturnus vulgaris). J. Endocrinol. 115, 211–220.
Hahn, T. P., Ball G. F. (1995) Changes in brain GnRH associated with photorefractoriness in house sparows (Passer domesticus). Gen. Comp. Endocrinol. 99, 349–363.
Kern, M. D. (1979) Seasonal changes in the reproductive system of the female white-crowned sparrow, Zonotrichia leucophrys gambelii, in captivity and in the field. 2. The incubation patch. Cell Tissue Res. 202, 379–398.
Kordonowy, L. L., McMurtry, J. P., Williams T. D. (2009) Variation in plasma leptin-like immunore-activity in free-living European starlings (Sturnus vulgaris). Gen. Comp. Endocrinol. 166, 47–53.
Lambrechts, M. M., Perret, P. (2000) Along photoperiod overrides non-photoperiodic factors in blue tits’ timing of reproduction. Proc. Biol. Sci. 267, 585–588.
Lambrechts, M. M., Perret, P., Maistre, M., Blondel, J. (1999) Do experiments with captive non-domesticated animals make sense without population field studies? A case study with blue tits’ breeding time. Proc. R. Soc. Lond. B 266, 1311–1315.
Maney, D. L., Richardson, R. D., Wingfield J. C. (1997) Central administration of chicken gonado-tropin-releasing hormone-II enhances courtship behavior in a female sparrow. Horm. Behav. 32, 11–18.
Meddle, S. L., Maney, D. L., Wingfield J. C. (1999) Effects of N-methyl-D-aspartate on luteinizing hormone release and Fos-like immunoreactivity in the male White-crowned sparrow (Zonotrichia leucophrys gambelii). Endocrinol. 140, 5922–5928.
Millam, J. R., Ottinger, M. A., Craig-Veit, C. B., Fan, Y., Chaiseha, Y., el Halawani, M. (1998) Multiple forms of GnRH are released from perifused medial basal hypothalamic/preoptic area (MBH/ POA) expiants in birds. Gen. Comp. Endocrinol. 111, 95–101.
Molnár, Gy. (1982) Populációökológiai vizsgálatok a Sturnus vulgarison. Doktori értekezés. JATE Állattani Tanszék, Szeged (in Hungarian).
Nicholls, T. J., Goldsmith, A. R., Dawson, A. (1988) Photorefractoriness in birds and comparison with mammals. Physiol. Rev. 68, 133–176.
Parry, D. M., Goldsmith, A. R., Millar, R. P., Glennie L. M. (1997) Immunocytochemical localization of GnRH precursor in the hypothalamus of European starlings during sexual maturation and photorefractoriness. J. Neuroendocrinal. 9, 235–243.
Pereyra, M. E., Sharbaugh, S. M., Hahn T. P. (2005) Interspecific variation in photo-induced GnRH plasticity among nomadic cardueline finches. Brain. Behav. Evol. 66, 35–49.
Perfito, N., Bentley, G. E., Hau, M. (2006) Tonic activation of brain GnRH immunoreactivity despite reduction of peripheral reproductive parameters in opportunistically breeding zebra finches. Brain Behav. Evol. 67, 123–134.
Phillmore, L. S., Hoshooley, J. S., Hahn, T. P., MacDougall-Shackleton, S.A. (2005) Atest of absolute photorefractoriness and photo-induced neural plasticity of song-control regions in black-capped chickadees (Poecile atricapillus). Can. J. Zool. 83, 747–753.
Riters, L. V., Eens, M., Pinxten, R., Duffy, D. L., Balthazart, J., Ball G. F. (2000) Seasonal changes in courtship song and the medial preoptic area in male European starlings (Sturnus vulgaris). Horm. Behav. 38, 250–261.
Robinson, J. E., Follett B. K. (1982) Photoperiodism in Japanese quail: the termination of seasonal breeding by photorefractoriness. Proc. R. Soc. Lond. B. Biol. Sci. 215, 95–116.
Sharp, P. J., Talbot, R. T., Main, G. M., Dunn, I. C., Fraser, H. M., Huskisson N. S. (1990) Physiological roles of chicken LHRH-I and -II in the control of gonadotropin release in the domestic chicken. J. Endocrinol. 124, 291–299.
Small, W. T., Sharp, P. J., Bentley, G. E., Millar, R. P., Tsutsui, K., Mura, E., Deviche, P. (2008) Photoperiod-independent hypothalamic regulation of luteinizing hormone secretion in a free-living sonoran desert bird, the rufous-winged sparrow (Aimophila carpalis). Brain. Behav. Evol. 71, 127–142.
Stevenson, T. J., Ball G. F. (2009) Anatomical localization of the effects of reproductive state, castration, and social milieu on cells immunoreactive for gonadotropin-releasing hormone-I in male European starlings (Sturnus vulgaris). J. Comp. Neurol. 517, 146–155.
Stevenson, T. J., Bernard, D. J., Ball G. F. (2009) Photoperiodic condition is associated with region-specific expression of GNRH1 mRNA in the preoptic area of the male starling (Sturnus vulgaris). Biol. Reprod. 81, 674–680.
Stevenson, T. J., Lynch, K. S., Lamba, P., Ball, G. F., Bernard D. J. (2009) Cloning of gonadotropin-releasing hormone I complementary DNAs in songbirds facilitates dissection of mechanisms mediating seasonal changes in reproduction. Endocrinol. 150, 1826–1833.
Stevenson, T. J., Macdougall-Shackleton, S. A. (2005) Season- and age-related variation in neural cGnRH-I and cGnRH-II immunoreactivity in house sparrows (Passer domesticus). Gen. Comp. Endocrinol. 143, 33–39.
Ubuka, T., Cadigan, P. A., Wang, A., Liu, J., Bentley G. E. (2009) Identification of European starling GnRH-I precursor mRNA and its seasonal regulation. Gen. Comp. Endocrinol. 162, 301–306.
Ubuka, T., Kim, S., Huang, Y., Reid, J., Jiang, J., Osugi, T., Chowdhury, V. S., Tsutsui, K., Bentley, G E. (2008) Gonadotropin-inhibitory hormone neurons interact directly with gonadotropin-releasing hormone-I and -II neurons in european starling brain. Endocrinol. 149, 268–278.
About this article
Cite this article
Pintér, O., Péczel, P. Seasonal Changes in Hypothalamic Gonadotropin-Releasing Hormone-I Immunoreactivity in Relation With Testicular Volume in Adult Male Free-Living European Starlings (Sturnus Vulgaris). BIOLOGIA FUTURA 61, 237–249 (2010). https://doi.org/10.1556/ABiol.61.2010.3.1
- European starling
- seasonal reproduction