Induced final maturation and ovulation in a small anabantoid teleost, the dwarf gourami, Colisa lalia. I. The effects of gonadotrophic preparations, LHRHa, steroids and thyroid hormones

Colisa lalia (Ham.) has been used as a model for the development of techniques for induced spawning that are applicable to small teleosts where ovulation requires prolonged exposure to suitable breeding conditions.Human chorionic gonadotrophin (hCG; 4 IU per fish) induced ovulation within 24 hours, whereas homologous pituitary extracts were relatively ineffective. When administered in saline ( 20 g per fish per injection), des-Gly10,[D-Ala6]- LHRH N-ethylamide (LHRHa) was ineffective, but it stimulated ovulation in a proportion of fish when administered ( 1.6 g per fish) as an emulsion in Freund's incomplete adjuvant (FIA). Together, these results suggest that ovulation requires the synthesis as well as the secretion of gonadotrophin in C. lalia.Long-term treatment with thyroid hormones appeared to enhance the ovulatory response to LHRHa in FIA, possibly by effects on the ovary; whereas the various steroids tested were ineffective at the dosages used     

Induced final maturation and ovulation in a small anabantoid teleost, the dwarf gourami (Colisa lalia). II. The modulatory effects of monoaminergic and opioid drugs on the responsiveness to LHRHa

There was evidence that the proportion of dwarf gourami, Colisa lalia (Hamilton), ovulating in response to the injection of an emulsion of LHRHa in Freund's incomplete adjuvant could be increased by concurrent treatment with dopamine antagonists, suggesting an inhibitory dopaminergic D₂ control of gonadotrophin secretion. There was also evidence that - and -adrenergic agonists may enhance the ovulatory response to LHRHa; on the other hand, - and -adrenergic antagonists were without effect at the dosages tested. There was also some inconsistent evidence for an inhibitory action of opioidergic systemsThis revised version was published online in October 2005 with corrections to the Cover Date.     

条纹密鲈卵黄蛋白原基因的克隆与检测

采用RT-PCR方法克隆并分析了条纹密鲈卵黄蛋白原(VTG)和β-肌动蛋白(β-actin)cDNA部分序列。获得的VTG cDNA序列片段长3 464 bp,全部处于编码区,编码1 150个氨基酸;β-actin cDNA序列片段长1 253 bp,编码375个氨基酸。使用活体与离体的实验方法,检测了VTG mRNA 转录情况,并以此评价雌二醇(E₂)、辛基酚(OP)、镉(Cd²⁺)和全氟辛烷磺酸类化合物(PFOS)引起的雌激素效应。结果显示,E₂和OP在活体和离体实验中均能剂量依赖性地诱导VTG mRNA表达。Cd²⁺仅在活体实验低剂量组诱导VTG mRNA表达,PFOS在活体和离体实验的各个浓度组均未见显著的VTG mRNA表达。结果表明,所诱导的雌激素效应强弱的排列顺序为E₂>OP>Cd²⁺。Cd²⁺的雌激素效应活体和离体实验的结果不一致,推测Cd²⁺引起雌激素效应的机理可能和E₂不同。条纹密鲈VTG cDNA对环境激素敏感,适合作为监测环境激素的生物标志物。