Nunez E A, Pomeranz H D, Gershon M D, Payette R F
Department of Anatomy and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York 10032.
Anat Rec. 1990 Apr;226(4):471-80. doi: 10.1002/ar.1092260409.
The distribution and cellular localization of the glycoprotein laminin were investigated by light and electron microscopic immunocytochemistry in the adult murine pituitary gland. Immunoblots confirmed that laminin was the only protein in the pituitary gland of the adult male mouse to react with antilaminin serum. Laminin immunoreactivity was demonstrated at the light microscopic level simultaneously with that of beta-follicle stimulating hormone (beta-FSH) and beta-luteinizing hormone (beta-LH). In addition to its distribution is basal laminae, laminin immunoreactivity was coincidently expressed in gonadotrophs with the immunoreactivities of beta-FSH and beta-LH. Electron microscopic immunocytochemistry was employed on aldehyde-fixed sections embedded in L.R. White. Sites of binding of primary antisera to laminin were identified with affinity-purified secondary antisera directly coupled to 20 nm particles of colloidal gold. Three antisera recognizing laminin were compared and found to result in an identical pattern of immunoreactivity. Laminin was found extracellularly only in formed basal laminae in all three lobes of the pituitary and was not found in extracellular matrices of connective tissue. Laminin immunoreactivity was also found intracellularly in gonadotrophs but in none of the other endocrine or non-endocrine cells of the anterior lobe. Within gonadotrophs, only secretory granules were labeled. The majority, but not all, secretory granules were labeled in each of the gonadotrophs examined, and the proportion of granules labeled with laminin could not be increased by doubling the concentration of anti-laminin serum. Laminin immunoreactivity segregated with the subset of secretory granules containing beta-FSH. In contrast, laminin immunoreactivity was absent in the smaller subset of secretory granules that contain serotonin.(ABSTRACT TRUNCATED AT 250 WORDS)
采用光镜和电镜免疫细胞化学方法研究了成年小鼠垂体中糖蛋白层粘连蛋白的分布及细胞定位。免疫印迹证实层粘连蛋白是成年雄性小鼠垂体中唯一能与抗层粘连蛋白血清发生反应的蛋白质。在光镜水平上，层粘连蛋白免疫反应性与β-促卵泡激素（β-FSH）和β-促黄体生成素（β-LH）的免疫反应性同时被证实。除了分布于基膜外，层粘连蛋白免疫反应性还与β-FSH和β-LH的免疫反应性同时在促性腺激素细胞中表达。对用L.R. White包埋的醛固定切片进行电镜免疫细胞化学研究。用直接偶联到20nm胶体金颗粒的亲和纯化二抗鉴定一抗与层粘连蛋白的结合位点。比较了三种识别层粘连蛋白的抗血清，发现它们产生相同的免疫反应模式。层粘连蛋白仅在垂体所有三个叶的已形成基膜的细胞外被发现，在结缔组织的细胞外基质中未发现。在促性腺激素细胞内也发现了层粘连蛋白免疫反应性，但在前叶的其他内分泌或非内分泌细胞中均未发现。在促性腺激素细胞内，仅分泌颗粒被标记。在所检查的每个促性腺激素细胞中，大多数但并非所有分泌颗粒都被标记，并且将抗层粘连蛋白血清浓度加倍并不能增加被层粘连蛋白标记的颗粒比例。层粘连蛋白免疫反应性与含有β-FSH的分泌颗粒亚群共分离。相反，在含有5-羟色胺的较小分泌颗粒亚群中不存在层粘连蛋白免疫反应性。（摘要截短于250字）
