Levine J E, Chappell P E, Schneider J S, Sleiter N C, Szabo M
Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, USA.
Front Neuroendocrinol. 2001 Apr;22(2):69-106. doi: 10.1006/frne.2001.0210.
Intracellular progesterone receptors (PRs) are ligand-inducible transcription factors that mediate the majority of the effects of progesterone (P) on neuroendocrine functions. During the past decade, evidence has accumulated which suggest that PRs can also be activated independently of P, by signals propagated through membrane-bound receptors to the interior of cells. The activation of PRs by this type of "cross-talk" mechanism has been implicated in the physiological regulation of several important neuroendocrine processes, including estrous behavior and periovulatory hormone secretions. We review evidence that both ligand-dependent and ligand-independent activation of PRs occurs in central neurons and in anterior pituitary cells and that the convergence and summation of these signals at the PR serves to integrate neural and endocrine signals which direct several critically important neuroendocrine processes. An integrative function for PRs is reviewed in several physiological contexts, including the display of lordosis behavior in female rodents, the neurosecretion of gonadotropin-releasing hormone surges, secretion of preovulatory gonadotropin surges, and release of periovulatory follicle stimulating hormone surges. The weight of evidence indicates that cross talk at the intracellular PR is an essential component of the integrative mechanisms that direct each of these neuroendocrine events. The recurrence of PR's integrative actions in several different physiological contexts suggests that other intracellular steroid receptors similarly function as integrators of neural and endocrine signals in other neuroendocrine processes.
细胞内孕酮受体（PRs）是配体诱导型转录因子，介导孕酮（P）对神经内分泌功能的大部分作用。在过去十年中，已有证据表明，PRs也可通过经膜结合受体向细胞内部传递的信号独立于P而被激活。这种“串扰”机制对PRs的激活与包括发情行为和排卵前后激素分泌在内的几个重要神经内分泌过程的生理调节有关。我们综述了相关证据，表明PRs的配体依赖性和配体非依赖性激活均发生在中枢神经元和垂体前叶细胞中，且这些信号在PR处的汇聚和累加有助于整合神经和内分泌信号，这些信号指导着几个至关重要的神经内分泌过程。在几种生理背景下对PRs的整合功能进行了综述，包括雌性啮齿动物中脊柱前凸行为的表现、促性腺激素释放激素激增的神经分泌、排卵前促性腺激素激增的分泌以及排卵前后促卵泡生成素激增的释放。证据的权重表明，细胞内PR处的串扰是指导这些神经内分泌事件中每一个事件的整合机制的重要组成部分。PRs的整合作用在几种不同的生理背景下反复出现，这表明其他细胞内类固醇受体在其他神经内分泌过程中同样作为神经和内分泌信号的整合器发挥作用。
