Soma Kiran K, Rendon Nikki M, Boonstra Rudy, Albers H Elliott, Demas Gregory E
Departments of Psychology and Zoology, Graduate Program in Neuroscience, and the Brain Research Centre, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
Department of Biology, Program in Neuroscience, and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA.
J Steroid Biochem Mol Biol. 2015 Jan;145:261-72. doi: 10.1016/j.jsbmb.2014.05.011. Epub 2014 Jun 11.
Historically, research on the neuroendocrinology of aggression has been dominated by the paradigm that the brain receives sex steroid hormones, such as testosterone (T), from the gonads, and then these gonadal hormones modulate behaviorally relevant neural circuits. While this paradigm has been extremely useful for advancing the field, recent studies reveal important alternatives. For example, most vertebrate species are seasonal breeders, and many species show aggression outside of the breeding season, when the gonads are regressed and circulating levels of gonadal steroids are relatively low. Studies in diverse avian and mammalian species suggest that adrenal dehydroepiandrosterone (DHEA), an androgen precursor and prohormone, is important for the expression of aggression when gonadal T synthesis is low. Circulating DHEA can be converted into active sex steroids within the brain. In addition, the brain can synthesize sex steroids de novo from cholesterol, thereby uncoupling brain steroid levels from circulating steroid levels. These alternative mechanisms to provide sex steroids to specific neural circuits may have evolved to avoid the costs of high circulating T levels during the non-breeding season. Physiological indicators of season (e.g., melatonin) may allow animals to switch from one neuroendocrine mechanism to another across the year. DHEA and neurosteroids are likely to be important for the control of multiple behaviors in many species, including humans. These studies yield fundamental insights into the regulation of DHEA secretion, the mechanisms by which DHEA affects behavior, and the brain regions and neural processes that are modulated by DHEA. It is clear that the brain is an important site of DHEA synthesis and action. This article is part of a Special Issue entitled 'Essential role of DHEA'.
从历史上看，对攻击行为神经内分泌学的研究一直受限于这样一种范式：大脑从性腺接收性类固醇激素，如睾酮（T），然后这些性腺激素调节与行为相关的神经回路。虽然这种范式对推动该领域发展极为有用，但最近的研究揭示了重要的其他可能性。例如，大多数脊椎动物是季节性繁殖者，许多物种在繁殖季节之外也会表现出攻击性，此时性腺退化，性腺类固醇的循环水平相对较低。对多种鸟类和哺乳动物物种的研究表明，肾上腺脱氢表雄酮（DHEA），一种雄激素前体和激素原，在性腺T合成较低时对攻击行为的表达很重要。循环中的DHEA可以在大脑内转化为活性性类固醇。此外，大脑可以从胆固醇从头合成性类固醇，从而使大脑类固醇水平与循环类固醇水平脱钩。这些向特定神经回路提供性类固醇的替代机制可能已经进化，以避免在非繁殖季节高循环T水平带来的成本。季节的生理指标（如褪黑素）可能使动物在一年中从一种神经内分泌机制切换到另一种。DHEA和神经类固醇可能对包括人类在内的许多物种的多种行为控制很重要。这些研究对DHEA分泌的调节、DHEA影响行为的机制以及受DHEA调节的脑区和神经过程产生了基本见解。很明显，大脑是DHEA合成和作用的重要场所。本文是名为“DHEA的重要作用”的特刊的一部分。
