Hurvitz Avshalom, Degani Gad, Goldberg Doron, Din Svetlana Yom, Jackson Karen, Levavi-Sivan Berta
Faculty of Agricultural, Food and Environmental Quality Sciences, Department of Animal Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
Gen Comp Endocrinol. 2005 Jan 1;140(1):61-73. doi: 10.1016/j.ygcen.2004.09.019.
The Russian sturgeon, Acipenser gueldenstaedtii, is a late-maturing Acipenseriformes. To elucidate the role of FSH and LH in its reproduction, we cloned its glycoprotein alpha-subunit (GPalpha) and gonadotropin beta-subunits (FSHbeta and LHbeta) using 5' and 3' RACE-PCR. The nucleotide sequences of the Russian sturgeon (st) GPalpha, FSHbeta, and LHbeta are 345, 384, and 411 bp long, encoding peptides of 91, 115, and 114 amino acids, respectively. The deduced amino acid sequence of each mature subunit showed high similarity with those of other teleosts. Sequence analysis showed that stFSHbeta is more similar to higher vertebrate FSHbetas (35-37%) than to higher vertebrate LHbetas (26-30%). The next objective of this work was to compare the development of sturgeon gonads at the very first stages of their growth with the expression of their gonadotropins. Sturgeons at ages 1, 2, 3 or 4 years were sacrificed. The expression of their gonadotropin beta-subunits was determined using quantitative real-time PCR, and their gonads were examined histologically, followed by a determination of the plasma levels of estradiol in females and 11-ketotestosterone (11-KT) in males. The expression levels of stFSHbeta subunit was found to be higher in fish at 3 and 4 years of age than in 1-year olds. mRNA levels of stLHbeta were higher than those of stFSHbeta in both genders. Moreover mRNA levels of stFSHbeta detected in females were significantly higher than those found in males. Even at age 4 years, all female Russian sturgeons tested contained gonads at the pre-vitellogenic stage, with small oocytes and very low levels of estradiol in the plasma. However, among the males, at ages 3 and 4 years, we found testes that contained spermatids and spermatozoa. Those males were found to have significantly high GSI (gonadosomatic index; gonadal weight as a percentage of BW) levels, stLHbeta expression and 11-KT levels.
俄罗斯鲟鱼（Acipenser gueldenstaedtii）是一种成熟较晚的鲟形目鱼类。为了阐明促卵泡激素（FSH）和促黄体生成素（LH）在其繁殖过程中的作用，我们利用5'和3' RACE-PCR技术克隆了其糖蛋白α亚基（GPα）和促性腺激素β亚基（FSHβ和LHβ）。俄罗斯鲟鱼（st）的GPα、FSHβ和LHβ的核苷酸序列长度分别为345、384和411 bp，分别编码91、115和114个氨基酸的肽段。推导的每个成熟亚基的氨基酸序列与其他硬骨鱼类的序列具有高度相似性。序列分析表明，stFSHβ与高等脊椎动物的FSHβ的相似性（35 - 37%）高于与高等脊椎动物的LHβ的相似性（26 - 30%）。这项工作的下一个目标是比较鲟鱼性腺在生长最初阶段的发育情况与其促性腺激素的表达。对1、2、3或4岁的鲟鱼进行宰杀。使用定量实时PCR测定其促性腺激素β亚基的表达，并对其性腺进行组织学检查，随后测定雌性的血浆雌二醇水平和雄性的11 - 酮睾酮（11 - KT）水平。发现3岁和4岁的鱼中stFSHβ亚基的表达水平高于1岁的鱼。在两性中，stLHβ的mRNA水平均高于stFSHβ。此外，在雌性中检测到的stFSHβ的mRNA水平显著高于雄性。即使在4岁时，所有接受测试的雌性俄罗斯鲟鱼的性腺都处于卵黄生成前期，有小卵母细胞且血浆中雌二醇水平极低。然而，在雄性中，3岁和4岁时，我们发现睾丸中含有精子细胞和精子。这些雄性的性腺指数（GSI；性腺重量占体重的百分比）水平、stLHβ表达和11 - KT水平均显著较高。
