McDonald J K, Klein K, Noe B D
Department of Anatomy and Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322.
Cell Tissue Res. 1995 Apr;280(1):159-70. doi: 10.1007/BF00304521.
Peptidyl-glycine alpha-amidating monooxygenase (PAM; EC 1.14.17.3) is an enzyme that catalyzes conversion of glycine-extended peptides to alpha-amidated bioactive peptides. Two peptides that are processed at their carboxyl-termini by this enzyme are neuropeptide Y and anglerfish peptide Y, both of which possess a C-terminal glycine that is used as a substrate for amidation. Results from previous reports have demonstrated that neuropeptide Y-like and anglerfish peptide Y-like immunoreactivities are present in the brain of anglerfish (Lophius americanus). Furthermore, neuropeptide Y-like peptides, namely anglerfish peptide Y and anglerfish peptide YG (the homologues of pancreatic polypeptide) are present in the islet organ of this species. Neuropeptide Y has also been localized in the anterior, intermediate and posterior lobes of the pituitary gland in a variety of species. In order to learn more about the distribution of the enzyme responsible for alpha amidation of these peptides in the brain and pituitary and to specifically investigate the relationship of this enzyme to peptide synthesizing endocrine cells of the anglerfish islet, we performed an immunohistochemical study using several antisera generated against different peptide sequences of the enzyme. PAM antisera labeled cells in the islet organ, pituitary and brain, and fibers in the brain and pituitary gland. The PAM staining pattern in the brain was remarkably similar to the distribution of neuropeptide Y immunoreactivity reported previously. Clusters of cells adjacent to vessels in the anterior pituitary displayed punctate PAM immunoreactivity while varicose fibers were observed in the pituitary stalk and neurohypophysis. Endocrine cells of the islet organ were differentially labeled with different PAM antisera. Comparison of the staining patterns of insulin, glucagon, and anglerfish peptide Y in the islet organ to PAM immunoreactivity suggests a distribution of forms of PAM enzyme in insulin and anglerfish peptide Y-containing cells, but no overlap with glucagon-producing cells. The results also indicate that PAM immunoreactivity is widely distributed in the brain, pituitary and islet organ of anglerfish in cells, that contain peptides that require presence of a C-terminal glycine for amidation.
肽基甘氨酸α-酰胺化单加氧酶（PAM；EC 1.14.17.3）是一种催化甘氨酸延伸肽转化为α-酰胺化生物活性肽的酶。两种在其羧基末端经该酶加工的肽是神经肽Y和安康鱼肽Y，二者均具有用作酰胺化底物的C末端甘氨酸。先前报告的结果表明，安康鱼（美洲狼鱼）大脑中存在神经肽Y样和安康鱼肽Y样免疫反应性。此外，该物种的胰岛器官中存在神经肽Y样肽，即安康鱼肽Y和安康鱼肽YG（胰多肽的同源物）。神经肽Y也已定位在多种物种垂体的前叶、中叶和后叶。为了更多地了解负责这些肽在大脑和垂体中α酰胺化的酶的分布，并特别研究该酶与安康鱼胰岛肽合成内分泌细胞的关系，我们使用针对该酶不同肽序列产生的几种抗血清进行了免疫组织化学研究。PAM抗血清标记了胰岛器官、垂体和大脑中的细胞，以及大脑和垂体中的纤维。大脑中的PAM染色模式与先前报道的神经肽Y免疫反应性分布非常相似。垂体前叶血管附近的细胞簇显示点状PAM免疫反应性，而在垂体柄和神经垂体中观察到曲张纤维。胰岛器官的内分泌细胞用不同的PAM抗血清进行了差异标记。将胰岛器官中胰岛素、胰高血糖素和安康鱼肽Y的染色模式与PAM免疫反应性进行比较，表明PAM酶的形式分布于含胰岛素和安康鱼肽Y的细胞中，但与产生胰高血糖素的细胞无重叠。结果还表明，PAM免疫反应性广泛分布于安康鱼的大脑、垂体和胰岛器官的细胞中，这些细胞含有需要C末端甘氨酸进行酰胺化的肽。
