Revol Agnès, Garza Rodríguez Maria de Lourdes, Hernández Montenegro Víctor, Aguilera Carlos, Barrera Saldaña Hugo, Mendoza Roberto
Departamento de Inmunología, Universidad Autónoma de Nuevo León, Facultad de Medicina, Av. Madero y Dr. A. Pequeño, Col. Mitras Centro, CP64460, Monterrey, México.
Comp Biochem Physiol A Mol Integr Physiol. 2005 Apr;140(4):423-9. doi: 10.1016/j.cbpb.2005.02.004. Epub 2005 Mar 23.
The alligator gar (Atractosteus spatula) is the largest freshwater fish inhabiting rivers draining into the Gulf of Mexico. This primitive fish shows a fast growth rate since its early larval stages. This is attributed to the action of growth hormone (GH), an anterior pituitary gland hormone responsible for linear growth in vertebrates that can also be expressed in extrapituitary adult tissues and in fish embryos. The present research was aimed at obtaining the GH coding sequence of the alligator gar and studying its expression through larval development. A cDNA was obtained by RT-PCR, cloned and sequenced. The alligator gar GH cDNA sequence shares 98% nucleotide similarity with that reported for Lepisosteus osseus, indicating a very slow evolution of the GH within the primitive fish, in contrast with the burst of changes observed in euteleosts. Using RT-PCR and RNA nuclease protection assays, GH transcripts were detected at very high levels in eggs, embryos and in several larval stages. These data suggest that the GH may play an important role during embryogenesis in fish. The better understanding of alligator gar larval physiology will facilitate the culture of larvae and juvenile gar and consequently may allow the restoration of their natural populations.
雀鳝（Atractosteus spatula）是栖息在流入墨西哥湾的河流中的最大淡水鱼。这种原始鱼类从幼体早期阶段就显示出快速的生长速度。这归因于生长激素（GH）的作用，生长激素是一种腺垂体激素，负责脊椎动物的线性生长，也可在垂体外的成年组织和鱼类胚胎中表达。本研究旨在获得雀鳝的生长激素编码序列，并研究其在幼体发育过程中的表达。通过逆转录聚合酶链反应（RT-PCR）获得了一个互补DNA（cDNA），进行了克隆和测序。雀鳝生长激素cDNA序列与骨鳞鱼（Lepisosteus osseus）报道的序列具有98%的核苷酸相似性，这表明在这种原始鱼类中生长激素的进化非常缓慢，这与在真骨鱼类中观察到的快速变化形成对比。使用RT-PCR和RNA核酸酶保护分析，在卵、胚胎和几个幼体阶段均检测到高水平的生长激素转录本。这些数据表明，生长激素可能在鱼类胚胎发生过程中发挥重要作用。更好地了解雀鳝幼体生理学将有助于幼体和幼鱼的养殖，从而可能有助于恢复它们的自然种群。
