Centre National de la Recherche Scientifique, Institute of Functional Genomics, Institut National de la Santé et de la Recherche Médicale, Universities of Montpellier 1 and 2, UMR-5203, F-34000 Montpellier, France.
Endocrinology. 2011 Dec;152(12):4789-99. doi: 10.1210/en.2011-1430. Epub 2011 Sep 27.
The secretion of endocrine hormones from pituitary cells finely regulates a multitude of homeostatic processes. To dynamically adapt to changing physiological status and environmental stimuli, the pituitary gland must undergo marked structural and functional plasticity. Endocrine cell plasticity is thought to primarily rely on variations in cell proliferation and size. However, cell motility, a process commonly observed in a variety of tissues during development, may represent an additional mechanism to promote plasticity within the adult pituitary gland. To investigate this, we used multiphoton time-lapse imaging methods, GH-enhanced green fluorescent protein transgenic mice and sexual dimorphism of the GH axis as a model of divergent tissue demand. Using these methods to acutely (12 h) track cell dynamics, we report that ovariectomy induces a dramatic and dynamic increase in cell motility, which is associated with gross GH-cell network remodeling. These changes can be prevented by estradiol supplementation and are associated with enhanced network connectivity as evidenced by increased coordinated GH-cell activity during multicellular calcium recordings. Furthermore, cell motility appears to be sex-specific, because reciprocal alterations are not detected in males after castration. Therefore, GH-cell motility appears to play an important role in the structural and functional pituitary plasticity, which is evoked in response to changing estradiol concentrations in the female.
垂体细胞内分泌激素的分泌精细地调节着许多体内平衡过程。为了动态适应生理状态和环境刺激的变化，垂体必须经历明显的结构和功能可塑性。内分泌细胞的可塑性被认为主要依赖于细胞增殖和大小的变化。然而，细胞迁移，一种在发育过程中常见于各种组织的过程，可能代表促进成年垂体内可塑性的另一种机制。为了研究这一点，我们使用多光子延时成像方法、GH 增强型绿色荧光蛋白转基因小鼠和 GH 轴的性别二态性作为不同组织需求的模型。使用这些方法在 12 小时内急性追踪细胞动力学，我们报告说，卵巢切除术诱导细胞迁移的剧烈和动态增加，这与 GH 细胞网络的大体重塑有关。这些变化可以通过雌激素补充来预防，并且与增加的网络连接性相关，这可以通过在多细胞钙记录期间增加协调的 GH 细胞活性来证明。此外，细胞迁移似乎是性别特异性的，因为在雄性大鼠去势后没有检测到相反的变化。因此，GH 细胞迁移似乎在对女性中不断变化的雌激素浓度的反应中发挥重要作用，促进了垂体的结构和功能可塑性。
