Morel G, Ouhtit A, Kelly P A
CNRS URA 1454-Neuroendocrinologie, Faculté de Médécine Lyon-Sud, Oullins, France.
Neuroendocrinology. 1994 Jan;59(1):78-84. doi: 10.1159/000126641.
Prolactin (PRL) receptors have been identified in both classical and nonclassical target organs. Actions of PRL on the secretion of anterior pituitary hormones have been reported. In order to confirm the presence of PRL receptors on specific cell types of the anterior pituitary, immunocytology on ultrathin frozen sections was carried out using monoclonal antibodies specific to the rat PRL receptor. Anterior pituitary glands were removed and fixed in 4% paraformaldehyde or 2.5% glutaraldehyde and postfixed in 1% osmium tetroxide. Tissues were frozen and ultrathin sections were made by cryoultramicrotomy. In anterior pituitary cells, all endocrine cell populations showed PRL-R-like immunoreactivity. The relative labeling frequency based on immunolabeling studies was somatotrophs > lactotrophs > thyrotrophs approximately corticotrophs > gonadotrophs. Within all endocrine cell types, no apparent differences could be observed in the subcellular localization of PRL-R-like immunoreactivity. At the subcellular level, gold particles, either isolated or in groups of two, were seen at the level of the plasma membrane, in the cytoplasmic matrix, in the vicinity of the endoplasmic reticulum and in the nucleus. The identification of receptors specific to PRL within different cells of the anterior pituitary raises the interesting possibility that PRL may act via an autocrine or paracrine network in regulating anterior pituitary function.
催乳素（PRL）受体已在经典和非经典靶器官中被鉴定出来。已有报道称PRL对垂体前叶激素分泌有作用。为了证实垂体前叶特定细胞类型上存在PRL受体，使用针对大鼠PRL受体的单克隆抗体对超薄冰冻切片进行了免疫细胞化学研究。切除垂体前叶并固定于4%多聚甲醛或2.5%戊二醛中，然后用1%四氧化锇后固定。组织经冷冻后，通过冷冻超薄切片机制备超薄切片。在垂体前叶细胞中，所有内分泌细胞群体均显示出PRL-R样免疫反应性。基于免疫标记研究的相对标记频率为：生长激素细胞＞催乳激素细胞＞促甲状腺激素细胞≈促肾上腺皮质激素细胞＞促性腺激素细胞。在所有内分泌细胞类型中，PRL-R样免疫反应性的亚细胞定位未见明显差异。在亚细胞水平上，在质膜、细胞质基质、内质网附近和细胞核中可见单个或成对的金颗粒。在垂体前叶不同细胞中鉴定出PRL特异性受体，这引发了一个有趣的可能性，即PRL可能通过自分泌或旁分泌网络调节垂体前叶功能。
