Department of Biology, University of Saskatchewan, S7N 5E2, Saskatoon, Saskatchewan, Canada.
Fish Physiol Biochem. 1996 Apr;15(2):157-65. doi: 10.1007/BF01875595.
A recombinant carp growth hormone (rcGH) was used to develop for a GH radioreceptor binding assay in the goldfish (Carassius auratus). Specific binding of(125)I-rcGH to goldfish liver membranes was a pH, time, temperature, and membrane protein dependent process. Scatchard and LIGAND analysis indicated a single class of high affinity and low capacity binding site, with an association constant (Ka) of 1.9×10(10) M(-1) and a maximum binding capacity (Bmax) of 9 fmol mg(-1) protein. Liver tissue displayed the highest(125)I-rcGH binding of all the tissues examined. Displacement of(125)I-rcGH with various unlabeled teleost and mammalian GHs and prolactins revealed that the goldfish hepatic binding site was highly specific for teleost GH. Intraperitoneal administration of 0.1, 1.0, and 10 μg rcGH g(-1) body weight to hypophysectomized goldfish resulted in a 27, 52, and 68% decrease in total binding sites, respectively. Injection of a high dose of rat prolactin (rPRL) (5 μg rPRL g(-1) body weight) also resulted in a 32% decrease in total binding sites. These results suggest that endogenous GH may have a role in the regulation of its own receptors in the goldfish.
重组鲤鱼生长激素（rcGH）被用于开发金鱼（Carassius auratus）的 GH 放射受体结合测定法。（125）I-rcGH 与金鱼肝膜的特异性结合是一个依赖 pH、时间、温度和膜蛋白的过程。Scatchard 和 LIGAND 分析表明存在一种单一类型的高亲和力和低容量结合位点，其缔合常数（Ka）为 1.9×10（10）M（-1），最大结合容量（Bmax）为 9 fmol mg（-1）蛋白。与所有检查的组织相比，肝脏组织显示出最高的（125）I-rcGH 结合。用各种未标记的硬骨鱼和哺乳动物 GH 和催乳素置换（125）I-rcGH 表明，金鱼肝结合位点对硬骨鱼 GH 具有高度特异性。对垂体切除的金鱼腹腔内注射 0.1、1.0 和 10 μg rcGH g（-1）体重分别导致总结合位点减少 27%、52%和 68%。注射高剂量的大鼠催乳素（rPRL）（5 μg rPRL g（-1）体重）也导致总结合位点减少 32%。这些结果表明，内源性 GH 可能在调节金鱼自身受体方面发挥作用。
