Villaplana Mariano, García Ayala Alfonsa, García Hernández Maria Pilar, Agulleiro Blanca
Department of Cell Biology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain.
J Morphol. 2003 Mar;255(3):347-57. doi: 10.1002/jmor.10067.
Growth hormone (GH), prolactin (PRL), and mammosomatotrope (MS) cells of gilthead sea bream, Sparus aurata, a teleost fish, were studied in specimens from hatching to 15 months (adults) using conventional electron microscopy and an immunogold method using anti-tilapia GH sera and anti-chum salmon PRL serum. MS cells, immunoreactive to both anti-GH sera and anti-PRL sera, had been first identified in fish in a previous study in newly hatched larvae and in older larvae and juvenile specimens of Sparus aurata by light microscopic immunocytochemistry. In the present work, MS cells reacted positively to immunogold label only in older larvae and juveniles and their secretory granules immunoreacted with both GH and PRL antisera or with only one of them. MS cells were ultrastructurally similar to the PRL cells, with which they coincided in time. This is the first report on the ultrastructural characterization of MS cells in fish. In adults, the secretory granules of GH cells (immunoreactive to anti-GH serum) were mainly round, of variable size, and had a homogeneous, highly electron-dense content. Irregularly shaped secretory granules were also present. PRL cells (immunoreactive to anti-PRL serum) were usually observed in a follicular arrangement; they showed few, small, and mainly round secretory granules with a homogeneous and high or medium electron-dense content. Some oval or elongated secretory granules were also observed. GH and PRL cells that showed involutive features were also found. In newly hatched larvae, GH, PRL, and MS cells could not be distinguished either by their ultrastructure or by the immunogold labeling of the secretory granules. In 1-day-old larvae, presumptive GH and PRL cells were observed according to their position in the pituitary gland. In 2-day-old larvae, a few cells showed some of the ultrastructural features described for GH and PRL cells of adults. During development, the number, size, and shape of the secretory granules in both cell types clearly increased and the organelles developed gradually. Some GH cells were found undergoing mitosis.
利用传统电子显微镜以及使用罗非鱼生长激素抗血清和大麻哈鱼催乳素抗血清的免疫金法，对硬骨鱼金头鲷从孵化到15个月（成鱼）阶段的生长激素（GH）细胞、催乳素（PRL）细胞和促乳生长激素细胞（MS）进行了研究。在之前一项研究中，通过光学显微镜免疫细胞化学技术，在新孵化的幼体以及金头鲷的大龄幼体和幼鱼标本中首次鉴定出对生长激素抗血清和催乳素抗血清均呈免疫反应的促乳生长激素细胞。在本研究中，促乳生长激素细胞仅在大龄幼体和幼鱼中对免疫金标记呈阳性反应，其分泌颗粒与生长激素和催乳素抗血清均发生免疫反应，或仅与其中一种发生免疫反应。促乳生长激素细胞在超微结构上与催乳素细胞相似，且在时间上与催乳素细胞一致。这是关于鱼类促乳生长激素细胞超微结构特征的首次报道。在成鱼中，生长激素细胞（对生长激素抗血清呈免疫反应）的分泌颗粒主要呈圆形，大小不一，内容物均匀、电子密度高。也存在形状不规则的分泌颗粒。催乳素细胞（对催乳素抗血清呈免疫反应）通常呈滤泡状排列；它们显示出少量、小且主要为圆形的分泌颗粒，内容物均匀，电子密度高或中等。也观察到一些椭圆形或细长形的分泌颗粒。还发现了呈现退化特征的生长激素细胞和催乳素细胞。在新孵化的幼体中，无法通过超微结构或分泌颗粒的免疫金标记来区分生长激素细胞、催乳素细胞和促乳生长激素细胞。在1日龄幼体中，根据其在垂体中的位置观察到推定的生长激素细胞和催乳素细胞。在2日龄幼体中，一些细胞呈现出成鱼生长激素细胞和催乳素细胞所描述的一些超微结构特征。在发育过程中，两种细胞类型的分泌颗粒数量、大小和形状明显增加，细胞器逐渐发育。发现一些生长激素细胞正在进行有丝分裂。
