Department of Biology, Georgia State University, Atlanta, GA 30303, USA.
Department of Biology, Georgia State University, Atlanta, GA 30303, USA.
Horm Behav. 2014 Jan;65(1):47-56. doi: 10.1016/j.yhbeh.2013.11.006. Epub 2013 Dec 5.
Seasonal changes in steroid hormones are known to have a major impact on social behavior, but often are quite sensitive to environmental context. In the bi-directionally sex changing fish, Lythrypnus dalli, stable haremic groups exhibit baseline levels of interaction. Status instability follows immediately after male removal, causing transiently elevated agonistic interactions and increase in brain and systemic levels of a potent fish androgen, 11-ketotestosterone (KT). Coupling KT implants with a socially inhibitory environment for protogynous sex change induces rapid transition to male morphology, but no significant change in social behavior and status, which could result from systemically administered steroids not effectively penetrating into brain or other tissues. Here, we first determined the degree to which exogenously administered steroids affect the steroid load within tissues. Second, we examined whether coupling a social environment permissive to sex change would influence KT effects on agonistic behavior. We implanted cholesterol (Chol, control) or KT in the dominant individual (alpha) undergoing sex change (on d0) and determined the effects on behavior and the degree to which administered steroids altered the steroid load within tissues. During the period of social instability, there were rapid (within 2 h), but transient effects of KT on agonistic behavior in alphas, and secondary effects on betas. On d3 and d5, all KT, but no Chol, treated females had male typical genital papillae. Despite elevated brain and systemic KT 5 days after implant, overall rates of aggressive behavior remained unaffected. These data highlight the importance of social context in mediating complex hormone-behavior relationships.
类固醇激素的季节性变化已知对社会行为有重大影响，但通常对环境背景非常敏感。在双向性别转变的鱼类，Lythrypnus dalli 中，稳定的后宫群体表现出基线水平的互动。在雄性移除后，地位不稳定立即出现，导致攻击性互动短暂增加，大脑和全身水平的一种强效鱼类雄激素 11-酮睾酮 (KT) 增加。将 KT 植入与促进性别转变的社会抑制环境相结合，可诱导快速过渡到雄性形态，但社会行为和地位没有显著变化，这可能是由于系统给予的类固醇不能有效渗透到大脑或其他组织中。在这里，我们首先确定了外源性类固醇在多大程度上影响组织内的类固醇负荷。其次，我们研究了社会环境是否有利于性别转变是否会影响 KT 对攻击行为的影响。我们在进行性别转变的优势个体（alpha）中植入胆固醇（Chol，对照）或 KT（on d0），并确定其对行为的影响，以及给予的类固醇在多大程度上改变了组织内的类固醇负荷。在社会不稳定期间，KT 对 alpha 中的攻击行为有快速（在 2 小时内）但短暂的影响，对 beta 有次要影响。在 d3 和 d5 时，所有 KT 处理的雌性，而不是 Chol 处理的雌性，都具有典型的雄性生殖器乳头。尽管植入后 5 天大脑和全身 KT 升高，但攻击性行为的总体发生率仍未受影响。这些数据强调了社会背景在调节复杂激素-行为关系中的重要性。
