Kumar R Sampath, Trant John M
Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, MD 21202, USA.
Gen Comp Endocrinol. 2004 Mar;136(1):82-9. doi: 10.1016/j.ygcen.2003.12.006.
A determination of the seasonal changes in the expression of the genes encoding the subunits of gonadotropic hormones is an important first step in the understanding of the molecular control of the onset of puberty and the reproductive cycle in fish. In this study, the abundance of transcripts encoding the glycoprotein hormone alpha (GpH-alpha), follicle-stimulating hormone beta (FSH-beta), and luteinizing hormone beta (LH-beta) subunits in pituitaries of female channel catfish were systematically tracked throughout an annual reproductive cycle. All three genes showed a concurrent elevation coinciding with the onset of ovarian recrudescence but then each showed a second elevation at different times of the ovarian cycle. In addition to the initial peak at recrudescence, the expression of FSH-beta and GpH-alpha gene peaked again during mid- and late-vitellogenic growth, respectively. The LH-beta gene expression remained low during the phases of regression and vitellogenic growth but was moderately elevated (7-fold) at the onset of ovarian recrudescence and dramatically elevated (36-fold) just prior to spawning (June-July) when the FSH-beta levels were at their lowest. The expression patterns of FSH-beta and LH-beta are remarkably similar to the ovarian expression of their respective receptors.
确定促性腺激素亚基编码基因表达的季节性变化，是理解鱼类青春期开始和生殖周期分子控制的重要第一步。在本研究中，在雌性斑点叉尾鮰垂体中，对编码糖蛋白激素α（GpH-α）、促卵泡激素β（FSH-β）和促黄体生成素β（LH-β）亚基的转录本丰度，在整个年度生殖周期中进行了系统追踪。所有这三个基因都显示出与卵巢复苏开始同时升高，但随后每个基因在卵巢周期的不同时间又出现了第二次升高。除了复苏时的初始峰值外，FSH-β和GpH-α基因的表达分别在卵黄生成中期和后期再次达到峰值。LH-β基因表达在退化期和卵黄生成期保持较低水平，但在卵巢复苏开始时适度升高（7倍），并在产卵前（6月至7月）FSH-β水平最低时急剧升高（36倍）。FSH-β和LH-β的表达模式与它们各自受体的卵巢表达非常相似。
