Cánepa Maximiliano Martín, Pandolfi Matías, Maggese María Cristina, Vissio Paula Gabriela
Laboratorio de Embriología Animal, Dpto. de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.
J Exp Zool A Comp Exp Biol. 2006 May 1;305(5):410-9. doi: 10.1002/jez.a.273.
Somatolactin (SL) is a pituitary hormone present exclusively in fish that is involved in different physiological processes. The role of SL was evaluated in Cichlasoma dimerus (Teleostei, Perciformes) exposed for 10 days to a black and white background (BB and WB). Changes in alpha-melanophore stimulating hormone (alphaMSH) and melanin concentrating hormone (MCH) cells were also analyzed for comparison with SL. A melanin dispersing effect was observed in fish exposed to a BB, while a concentrating one was observed in those exposed to a WB. By Western blot, three SL-immunoreactive (ir) bands (32, 28 and 23.5 kD) were evidenced. Pituitary SL-ir levels were 2.66- and 2.67-fold greater in the 32 Kd and 28 kD bands, respectively, in BB fish compared with those of WB fish. The SL-ir 23.5 Kd band was not included in the analysis because of its unknown identity. In addition, SL-ir cell number and area were significantly higher in the BB condition (BB 22.73+/-1.46, WB 7.37+/-0.54 and BB 27.39+/-1.00 microm2; WB: 16.61+/-0.65 microm2). No significant differences were observed in the number of the hypothalamic MCH-ir neurons. However, a significant difference was observed in their nuclear area (BB 11.61+/-0.42 microm2, WB 17.80+/-0.84 microm2). alphaMSH-ir cells showed a marked increased in number (BB 35.96+/-1.22, WB 24.36+/-1.04), but no significant differences were observed in the cell area. In conclusion, this study presented clear evidence towards a possible involvement of SL in the adaptation to background colors in teleost together with alphaMSH and MCH.
生长抑素（SL）是一种仅存在于鱼类中的垂体激素，参与不同的生理过程。研究评估了暴露于黑白背景（BB和WB）10天的双斑丽体鱼（硬骨鱼纲，鲈形目）中SL的作用。还分析了α-促黑素细胞激素（αMSH）和促黑素浓缩激素（MCH）细胞的变化，以便与SL进行比较。在暴露于BB的鱼中观察到黑色素分散效应，而在暴露于WB的鱼中观察到黑色素浓缩效应。通过蛋白质免疫印迹法，发现了三条SL免疫反应性（ir）条带（32、28和23.5 kD）。与WB鱼相比，BB鱼中32 Kd和28 kD条带中的垂体SL-ir水平分别高2.66倍和2.67倍。由于其身份不明，未将23.5 Kd的SL-ir条带纳入分析。此外，BB条件下的SL-ir细胞数量和面积显著更高（BB为22.73±1.46，WB为7.37±0.54，BB为27.39±1.00平方微米；WB为16.61±0.65平方微米）。下丘脑MCH-ir神经元的数量未观察到显著差异。然而，观察到它们的核面积存在显著差异（BB为11.61±0.42平方微米，WB为17.80±0.84平方微米）。αMSH-ir细胞数量显著增加（BB为35.96±1.22，WB为24.36±1.04），但细胞面积未观察到显著差异。总之，本研究提供了明确证据，表明SL可能与αMSH和MCH一起参与硬骨鱼对背景颜色的适应。
