Steroid Sensitive Sites in the Avian Brain: Does the Distribution of the Estrogen Receptor α and β Types Provide Insight into Their Function?
- 1 July 1999
- journal article
- Published by S. Karger AG in Brain, Behavior and Evolution
- Vol. 54 (1) , 28-40
- https://doi.org/10.1159/000006609
Abstract
Studies in avian species have often been useful in elucidating basic concepts relevant to the regulation of reproductive behaviors by sex steroid hormones. Once a link between a steroid hormone and a behavioral response has been established, one can use the localization of steroid hormone receptors in the brain to facilitate the identification of neural circuits that control behavior. The recent identification of a second type of estrogen receptor called estrogen receptor β or ERβ has raised new issues about the action of steroid hormones in the brain. A hypothesis has been proposed by Kuiper et al. [1998] based on studies in mammalian species suggesting that ERα (the name given to the ER that was previously described) is important for reproduction while ERβ is more important for non-reproductive functions. In this paper we apply this hypothesis more generally by examining possible functions of ERβ in avian species. We have initiated studies of the ERβ in the brain of two avian species, the Japanese quail (Coturnix japonica) and the European starling (Sturnus vulgaris). ERβ was cloned in both species and the mRNA for this receptor type was localized in the brain employing in situ hybridization histochemistry methods. In both species ERβ was found to be diffusely present in telencephalic areas consistent with a role for this receptor subtype in cognitive functions. However, ERβ mRNA was also found in many brain areas that are traditionally thought to be important in the regulation of reproductive functions such as the preoptic region, the bed nucleus of the stria terminalis and the nucleus taeniae. Of the two receptor types, only mRNA for ERα was observed in the telencephalic vocal control nucleus HVc of male starlings. Steroid receptors in this nucleus are thought to be an example of an evolutionary specialization that has evolved to coordinate the production of courtship vocalizations with other aspects of reproduction. The lack of ERβ mRNA expression in HVc is consistent with the hypothesis that ERα is preferentially involved in reproductive behaviors while ERβ is involved in the steroid regulation of other neural functions. However, the widespread occurrence of ERβ in other nuclei involved in reproductive function suggests that one must be cautious about the general applicability of the above hypothesis until more is known about ERβ function in these other nuclei.Keywords
This publication has 21 references indexed in Scilit:
- Generation and reproductive phenotypes of mice lacking estrogen receptor βProceedings of the National Academy of Sciences, 1998
- For Whom The Bird SingsNeuron, 1998
- Comparative distribution of estrogen receptor-? and -? mRNA in the rat central nervous systemJournal of Comparative Neurology, 1997
- The Distribution of Estrogen Receptor- mRNA in Forebrain Regions of the Estrogen Receptor- Knockout MouseEndocrinology, 1997
- Human Estrogen Receptor -Gene Structure, Chromosomal Localization, and Expression PatternJournal of Clinical Endocrinology & Metabolism, 1997
- Differential Ligand Activation of Estrogen Receptors ERα and ERβ at AP1 SitesScience, 1997
- Motor-driven gene expressionProceedings of the National Academy of Sciences, 1997
- Zebra finch estrogen receptor cDNA: Cloning and mRNA expressionThe Journal of Steroid Biochemistry and Molecular Biology, 1996
- Cloning of a novel receptor expressed in rat prostate and ovary.Proceedings of the National Academy of Sciences, 1996
- Molecular cloning and characterization of Japanese eel estrogen receptor cDNAMolecular and Cellular Endocrinology, 1996