Zuasti A, Jara J R, Ferrer C, Solano F
Department of Cellular Biology, Faculty of Medicine, University of Murcia, Spain.
Pigment Cell Res. 1989 Mar-Apr;2(2):93-9. doi: 10.1111/j.1600-0749.1989.tb00168.x.
An optical, ultrastructural, and biochemical study of the melanin accumulation nodules found in the kidney of the teleost fish Sparus auratus is presented. These nodules are randomly distributed in the interstitium of the renal tissue. They are formed by large aggregates of cells replete with melanin granules. The melanin granules occur singly or also in aggregates inside the cells. Most of the granules are electron-dense, but sometimes small electron-lucent spaces within them can be seen. Some secondary lysosomes and dendritic processes can also be observed. Biochemical studies have proved for the first time the existence of measurable tyrosinase activity in those nodules. That activity was assayed using three methods: tyrosine hydroxylation, dopa oxidation, and melanin formation. Furthermore, inhibitors of well-characterized plant and animal skin tyrosinases were effective agents for inhibiting those activities in fish kidney preparations. This finding supports the notion of the existence of true tyrosinase in the melanin accumulation nodules of this tissue. Taking into account the results obtained, the origin and functions of the melanin-containing cells found in the teleost fish kidney are discussed.
本文展示了对硬骨鱼金头鲷肾脏中黑色素积累结节的光学、超微结构和生化研究。这些结节随机分布于肾组织间质中。它们由充满黑色素颗粒的大量细胞聚集体构成。黑色素颗粒在细胞内单个存在或也聚集成团。大多数颗粒电子密度高，但有时可见其中有小的电子透亮区。还可观察到一些次级溶酶体和树突状突起。生化研究首次证明这些结节中存在可测量的酪氨酸酶活性。该活性通过三种方法测定：酪氨酸羟化、多巴氧化和黑色素形成。此外，特征明确的植物和动物皮肤酪氨酸酶抑制剂是抑制鱼肾制剂中这些活性的有效试剂。这一发现支持了该组织黑色素积累结节中存在真正酪氨酸酶的观点。考虑到所获结果，讨论了硬骨鱼肾脏中含黑色素细胞的起源和功能。
