Growth regulation in the gobiid teleost, Gillichthys mirabilis: roles of growth hormone, hepatic growth hormone receptors and insulin-like growth factor-I.
Growth regulation in the gobiid teleost, Gillichthys mirabilis: roles of growth hormone, hepatic growth hormone receptors and insulin-like growth factor-I.
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DOI：
10.1677/joe.0.1310057
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发表时间：
1991-10
期刊：
影响因子：
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通讯作者：
E. S. Gray;K. Kelley
中科院分区：
文献类型：
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作者：
E. S. Gray;K. Kelley
研究了生长激素对硬骨鱼Gillichthys mirabilis肝脏生长激素受体、胰岛素样生长因子-I（IGF-I）活性和软骨生长的调节作用。切除垂体G.每隔一天用生理盐水载体或用10、100或1000 ng罗非鱼GH（tGH）/g注射mirabilis，持续2-3周。通过体重和身长增加判断，垂体切除抑制生长，增加tGH剂量刺激生长。通过125 I标记的tGH结合测定，垂体切除术使肝GH受体降低50%。tGH注射后24 h观察到结合的额外剂量依赖性减少，但MgCl 2剥离膜表明外源性tGH的受体占据。IGF-I的活性，测量35 SO 4掺入口腔软骨外植体在体外，垂体切除术降低50%，并增加到200%的完整的对照水平后，注射1000 ng tGH/g。在第二个实验中，35 SO 4掺入垂体切除的鱼注射10，100或1000 ng tGH/g的口腔软骨刺激到完整的控制水平。还评估了喂养和tGH注射对口腔软骨对重组牛IGF-I（rbIGF-I; 10-1000 ng/ml）的体外反应性的影响。喂食鱼的口腔软骨呈抛物线剂量-反应曲线，而饥饿鱼的口腔软骨具有较低的35 SO 4掺入基础率和线性剂量-反应关系。切除垂体G.紫茉莉对rbIGF-I的反应明显减弱，注射tGH后恢复，表明动物的GH状态对靶组织对IGF-I的敏感性很重要。由于其与其他脊椎动物系统的相似性，G。mirabilis提出了一个很好的硬骨鱼生长调节和生长激素和IGF-I的功能和相互作用的模型。
Studies of the teleost Gillichthys mirabilis were undertaken to assess the role of GH in regulating hepatic GH receptors, insulin-like growth factor-I (IGF-I) activity and cartilage growth. Hypophysectomized G. mirabilis were injected with saline vehicle or with 10, 100 or 1000 ng tilapia GH (tGH)/g every other day for 2-3 weeks. Growth, judged by increased body weight and length, was inhibited by hypophysectomy and stimulated by increasing tGH doses. Hepatic GH receptors, measured by 125I-labelled tGH binding, were decreased 50% by hypophysectomy. An additional dose-dependent reduction in binding was observed 24 h after tGH injection, but MgCl2 stripping of membranes suggested receptor occupation by exogenous tGH. IGF-I activity, measured by 35SO4 incorporation into oral cartilage explants in vitro, was decreased 50% by hypophysectomy and increased to 200% of intact control levels after injection of 1000 ng tGH/g. In a second experiment, 35SO4 incorporation by oral cartilage from hypophysectomized fish injected with 10, 100 or 1000 ng tGH/g was stimulated to intact control levels. Effects of feeding and tGH injection on in-vitro responsiveness of oral cartilage to recombinant bovine IGF-I (rbIGF-I; 10-1000 ng/ml) were also assessed. Oral cartilage from fed fish showed a parabolic dose-response curve, whereas oral cartilage from starved fish had a lower basal rate of 35SO4 incorporation and a linear dose-response relationship. Oral cartilage from hypophysectomized G. mirabilis showed a significantly attenuated response to rbIGF-I which was restored by tGH injection, suggesting that the GH status of the animal is important for sensitivity of target tissue to IGF-I. Because of its similarity to other vertebrate systems, G. mirabilis presents a good teleost model of growth regulation and of the functions and interactions of GH and IGF-I.