Vallarino M, Delbende C, Bunel D T, Ottonello I, Vaudry H
Istituto di Anatomia Comparata, Università Degli Studi di Genova, Italy.
Peptides. 1989 Nov-Dec;10(6):1223-30. doi: 10.1016/0196-9781(89)90016-8.
We have investigated the presence of ACTH, alpha-MSH and beta-endorphin, three peptides which derive from the multifunctional precursor protein proopiomelanocortin (POMC) in the brain of the rainbow trout Salmo gairdneri. Using both the indirect immunofluorescence and peroxidase-antiperoxidase techniques, a discrete group of positive cells was identified in the hypothalamus, within the anterior part of the nucleus lateralis tuberis. alpha-MSH-containing neurons represented the most abundant immunoreactive subpopulation. Coexistence of alpha-MSH, ACTH and beta-endorphin was observed in the lateral part of the nucleus. ACTH- and beta-endorphin-containing cells were mainly distributed in the rostral and caudal regions of the nucleus. In the medial portion of the nucleus lateralis tuberis, numerous cells were only stained for alpha-MSH. Moderate to dense plexuses of immunoreactive fibers were observed in the ventral thalamus and the floor of the hypothalamus. Some of these fibers projected towards the pituitary. The concentrations of ACTH, alpha-MSH and beta-endorphin-like immunoreactivities were measured in microdissected brain regions by means of specific radioimmunoassays. Diencephalon, mesencephalon and medulla oblongata extracts gave dilution curves which were parallel to standard curves. The highest concentrations of POMC-derived peptides were found in the diencephalon (alpha-MSH: 4.28 +/- 0.43 ng/mg prot.; ACTH: 1.08 +/- 0.09 ng/mg prot.; beta-endorphin: 1.02 +/- 0.1 ng/mg prot.), while lower concentrations were detected in the mesencephalon, medulla oblongata and telencephalon. The present results demonstrate that various peptides derived from POMC coexist within the same cell bodies of the fish hypothalamus. Taken together, these data suggest that expression and processing of POMC in the fish brain is similar to that occurring in pituitary melanotrophs.
我们研究了促肾上腺皮质激素（ACTH）、α-促黑素（α-MSH）和β-内啡肽在虹鳟鱼脑内的存在情况，这三种肽均源自多功能前体蛋白阿黑皮素原（POMC）。运用间接免疫荧光和过氧化物酶-抗过氧化物酶技术，在下丘脑外侧结节核前部内鉴定出一组离散的阳性细胞。含α-MSH的神经元是最丰富的免疫反应性亚群。在该核的外侧部分观察到α-MSH、ACTH和β-内啡肽共存。含ACTH和β-内啡肽的细胞主要分布在该核的头端和尾端区域。在外侧结节核的内侧部分，许多细胞仅对α-MSH呈阳性染色。在腹侧丘脑和下丘脑底部观察到中等至密集的免疫反应性纤维丛。其中一些纤维伸向垂体。通过特定的放射免疫测定法测量了显微解剖的脑区中ACTH、α-MSH和β-内啡肽样免疫反应性的浓度。间脑、中脑和延髓提取物给出的稀释曲线与标准曲线平行。POMC衍生肽的最高浓度见于间脑（α-MSH：4.28±0.43 ng/mg蛋白；ACTH：1.08±0.09 ng/mg蛋白；β-内啡肽：1.02±0.1 ng/mg蛋白），而在中脑、延髓和端脑检测到的浓度较低。目前的结果表明，源自POMC的各种肽共存于鱼类下丘脑的同一细胞体中。综上所述，这些数据表明鱼类脑中POMC的表达和加工与垂体黑素细胞中的情况相似。
