VITELLOGENIN SYNTHESIS AND REGULATION BY PITUITARY HORMONES IN HEPATOCYTE CULTURES IN FISH

用虹鳟鱼和鳗鱼的原代肝细胞培养物研究了雌二醇（E_2）对卵黄蛋白原（Vg）的诱导作用。特别注意阐明垂体激素和细胞外和细胞内Ca离子参与E_2合成Vg。取得了如下结果：1.在培养液中添加E_2能有效地诱导虹鳟鱼Vg的合成，而对鳗鱼Vg的诱导则无效。E_2与生长激素和/或催乳素共同作用显著促进鳗鲡Vg的合成.在假手术组，E_2可诱导Vg合成，而在去垂体组，则无Vg合成.当培养液中Ca浓度在0 ~ 10 mM之间变化时，Vg合成呈浓度依赖性。在5 mM Ca. 4下获得最大合成。Vg的合成被特异性抑制哇巴因或La的孵育培养基中。这些结果直接表明垂体激素（至少在鳗鱼中）和钙离子参与了Vg的合成。这些发现有助于阐明鱼类Vg合成的机制。

Vitellogenin (Vg) induction by estradiol-17 beta (E_2) was examined in primary hepatocyte cultures using rainbow trout and eels. Special attention was directed to elucidating the involvement of pituitary hormones and extracellular and intracellular Ca ions in Vg synthesis by E_2. The following results have been obtained.1. The addition of E_2 to the incubation medium actively induced Vg synthesis in rainbow trout, while the same treatment failed in Vg induction in eels. The addition of E_2 with growth hormone and/or prolactin markedly stimulated Vg synthesis in eels.2. Although the administration of E_2 resulted in Vg synthesis in sham-operated eels, no Vg synthesis occurred in hypophysectomized eels.3. When Ca concentrations in the incubation medium were changed between O and 10 mM,Vg synthesis was in a concentration-dependent way. The maximum synthesis was obtained at 5mM Ca.4. Vg synthesis was peculiarly inhibited by the addition of ouabain or La to the incubation medium. proteins other than Vg were hardly affected by these reagents.These results directly indicate the involvement of pituitary hormones, at least in eels, and calcium ions in Vg synthesis. These findings contribute to the elucidation of mechanisms of Vg synthesis in fish.