Chanat E, Cozzi M G, Sion B, de Monti M, Zanini A, Duval J
Laboratoire d'Endocrinologie Moléculaire, CNRS UA 256, Rennes, France.
Biochimie. 1988 Oct;70(10):1361-8. doi: 10.1016/0300-9084(88)90007-7.
Cultured gonadotrope cells from 14 day old female rat pituitaries have been shown to release a highly acidic protein when incubated with LHRH: the gonadotrope polypeptide (GP 87). Moreover, a new tyrosine-sulfated acidic protein, secretogranin II (Sg II), clearly distinct from the chromogranin species, was described in the secretory granule matrix of endocrine cells secreting peptide hormones by the regulated pathway. Recently, the release of Sg II from female rat pituitary stimulated by LHRH was demonstrated in vitro. Several physicochemical (Mr; pI) and biological (cellular localization in the pituitary; LHRH-stimulated release) properties are common to Sg II and GP 87. To verify if these 2 polypeptides are similar or distinct components, other physicochemical characteristics (heat-stability, sulfation, phosphorylation) were compared using isotope incorporation followed by either 1- or 2-dimensional polyacrylamide gel electrophoresis and autoradiography. Furthermore, the similarity of GP 87 to Sg II was studied by immunoblotting on nitrocellulose sheets following electrophoresis of intracellular and secreted proteins. Antisera raised against bovine Sg II (extracted from whole pituitaries) and against rat GP 87 (released into the medium of cultured pituitary cells stimulated by LHRH) were used. The overall data presented here suggest that GP 87 is the Sg II form contained in, and released by, gonadotrope cells.
已证明，来自14日龄雌性大鼠垂体的培养促性腺激素细胞在与促黄体生成素释放激素（LHRH）一起孵育时会释放一种高度酸性的蛋白质：促性腺激素细胞多肽（GP 87）。此外，一种新的酪氨酸硫酸化酸性蛋白质，即分泌粒蛋白II（Sg II），与嗜铬粒蛋白种类明显不同，在通过调节途径分泌肽类激素的内分泌细胞的分泌颗粒基质中被发现。最近，体外实验证明了LHRH刺激雌性大鼠垂体释放Sg II。Sg II和GP 87具有一些共同的物理化学性质（分子量；等电点）和生物学性质（在垂体中的细胞定位；LHRH刺激释放）。为了验证这两种多肽是相似还是不同的成分，使用同位素掺入，随后进行一维或二维聚丙烯酰胺凝胶电泳和放射自显影，比较了其他物理化学特性（热稳定性、硫酸化、磷酸化）。此外，在对细胞内和分泌蛋白进行电泳后，通过在硝酸纤维素膜上进行免疫印迹研究了GP 87与Sg II的相似性。使用了针对牛Sg II（从整个垂体中提取）和大鼠GP 87（释放到受LHRH刺激的培养垂体细胞培养基中）产生的抗血清。此处呈现的总体数据表明，GP 87是促性腺激素细胞所含并释放的Sg II形式。
