Raghay Kawtar, García-Caballero Tomás, Nogueiras Rubén, Morel Gérard, Beiras Andrés, Diéguez Carlos, Gallego Rosalía
Department of Morphological Sciences, University Clinical Hospital, University of Santiago de Compostela, c/S. Francisco, 15782 Santiago de Compostela, Spain.
Histochem Cell Biol. 2006 Mar;125(3):239-46. doi: 10.1007/s00418-005-0044-6. Epub 2005 Sep 27.
Ghrelin, the endogenous ligand of the growth hormone secretagogue receptor (GHS-R), is a 28 amino acid peptide originally isolated from rat stomach that has been primarily involved in the central neuroregulation of GH secretion and food intake. Previous studies demonstrated that ghrelin has a widespread expression in different normal cells and tissues, as well as in gastric, thyroid, testicular, breast and lung neoplasias. In the current study, we use molecular biology to detect ghrelin transcripts expression in rats, and immunohistochemical techniques to investigate the cellular distribution of this peptide in rat and human thyroid and parathyroid glands and tumours. Ghrelin was localized in thyroid C cells and in parathyroid cells. Thyroid carcinomas (medullar, follicular and papillary) and parathyroid adenomas also showed intense and diffuse immunostaining for ghrelin. These data provide direct morphological evidence that ghrelin may well be acting in a paracrine fashion in the regulation of thyroid follicular cell function. The diffuse ghrelin immunostaining found in the parathyroid gland opens up the possibility of its secretion to the bloodstream or its involvement in the regulation of the parathyroid function. Overall, expression of ghrelin in human and rat thyroid and parathyroid glands is highly suggestive of a conserved role of this molecule in the regulation of thyroid and parathyroid cell function.
胃饥饿素是生长激素促分泌素受体（GHS-R）的内源性配体，是一种最初从大鼠胃中分离出的含28个氨基酸的肽，主要参与生长激素分泌和食物摄入的中枢神经调节。先前的研究表明，胃饥饿素在不同的正常细胞和组织以及胃癌、甲状腺癌、睾丸癌、乳腺癌和肺癌中广泛表达。在本研究中，我们使用分子生物学方法检测大鼠胃饥饿素转录本的表达，并采用免疫组织化学技术研究该肽在大鼠和人类甲状腺及甲状旁腺及其肿瘤中的细胞分布。胃饥饿素定位于甲状腺C细胞和甲状旁腺细胞中。甲状腺癌（髓样癌、滤泡癌和乳头状癌）和甲状旁腺腺瘤也显示出对胃饥饿素强烈且弥漫的免疫染色。这些数据提供了直接的形态学证据，表明胃饥饿素很可能以旁分泌方式调节甲状腺滤泡细胞功能。在甲状旁腺中发现的弥漫性胃饥饿素免疫染色表明其可能分泌入血液或参与甲状旁腺功能的调节。总体而言，胃饥饿素在人和大鼠甲状腺及甲状旁腺中的表达强烈提示该分子在调节甲状腺和甲状旁腺细胞功能方面具有保守作用。
