Pisam M, Auperin B, Prunet P, Rentier-Delrue F, Martial J, Rambourg A
Département de Biologie Cellulaire et Moléculaire du CEA Centre d'Etudes de Saclay Gif-sur-Yvette, France.
Anat Rec. 1993 Feb;235(2):275-84. doi: 10.1002/ar.1092350211.
Tilapia (Oreochromis niloticus), 21 g average body weight, were divided into two groups. A group was maintained in fresh water, whereas another group was adapted for 2 weeks to 20% salt water. Among the latter, fishes were injected every 2 days for a week with tilapia prolactin (ti-PRL I). Gills were prepared for electron microscopy in order to determine the types and surface areas of chloride cells in each experimental condition. Two types of chloride cells, the alpha and beta cells were easily distinguished on the basis of their location and ultrastructural features in the gills of freshwater fishes, while only one type of cell, the saltwater alpha cells presumably derived from the transformation of the freshwater alpha cells, were encountered in saltwater adapted animals. After PRL injection of saltwater adapted fishes, small chloride cells, which displayed ultrastructural features similar to those of beta cells in freshwater tilapia, reappeared in interlamellar regions of the gills. In the same experimental conditions, the voluminous saltwater alpha cells showed a tendency to resume ultrastructural features more characteristic of the freshwater alpha cells from which they were derived. These observations tend to indicate that prolactin behaves as a "freshwater adapting hormone" and that beta cells are specifically involved in fish adaptation to freshwater living conditions.
平均体重为21克的罗非鱼（尼罗罗非鱼）被分为两组。一组饲养在淡水中，而另一组在20%的盐水中适应2周。在后者中，鱼每隔两天注射一次罗非鱼催乳素（ti-PRL I），持续一周。制备鳃用于电子显微镜检查，以确定每种实验条件下氯细胞的类型和表面积。在淡水鱼的鳃中，根据氯细胞的位置和超微结构特征，很容易区分出两种类型的氯细胞，即α细胞和β细胞，而在适应盐水的动物中，只发现了一种类型的细胞，即盐水α细胞，推测它是由淡水α细胞转化而来的。对适应盐水的鱼注射催乳素后，在鳃的片层间区域重新出现了小氯细胞，其超微结构特征与淡水罗非鱼的β细胞相似。在相同的实验条件下，大量的盐水α细胞显示出恢复其来源的淡水α细胞更具特征性的超微结构特征的趋势。这些观察结果倾向于表明催乳素起着“适应淡水的激素”的作用，并且β细胞特别参与鱼类对淡水生活条件的适应。
