Changes in circulating insulin-like growth factor-1 and its binding proteins in yearling rainbow trout during spring under natural and manipulated photoperiods and their relationships with gill Na+, K+-ATPase and body size
Changes in circulating insulin-like growth factor-1 and its binding proteins in yearling rainbow trout during spring under natural and manipulated photoperiods and their relationships with gill Na+, K+-ATPase and body size
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DOI：
10.1016/j.cbpa.2022.111205
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发表时间：
2022-03-31
影响因子：
2.3
通讯作者：
Shimizu, Munetaka
中科院分区：
文献类型：
--
作者：
Cui, Wenda;Takahashi, Eisuke;Shimizu, Munetaka
鲑鱼的银化作用在春季发生，以响应光周期的增加，为海洋生物做好准备。银化与生长激素和胰岛素样生长因子 (IGF)-1 介导的低渗透压调节能力增强和生长潜力增强相关。虹鳟鱼对光周期诱导的银化相关变化特别不敏感，例如鳃 Na+,K+-ATP 酶 (NKA) 的激活。我们测量了春季暴露于自然和人工光周期的一岁虹鳟鱼的循环 IGF-1 和 IGFBP-2b 水平，并将这些水平与鳃 NKA 活性和体型相关联。尽管光周期操纵对体型和循环IGF-1和IGFBP-2b的影响可以忽略不计，但它们与模拟自然光周期下鱼的鳃NKA活性呈正相关。接下来，我们对一岁虹鳟鱼进行坑标记，并给它们喂食有限的配给量或在自然光照条件下喂饱它们。 4月，饱食组鳃NKA活性高于限制组，且与体大小和生长速度呈正相关。此外，循环IGFBP-2b与鳃NKA、大小和生长呈正相关，而循环IGF-1仅与大小和生长相关。 5 月至 6 月，循环 IGF-1 与生长之间的关系加强，表明当 4 月鳃 NKA 激活时，IGF-1-生长关系被破坏。另外两个 IGFBP 与生长参数相关，但与鳃 NKA 活性无关。本研究表明，春季期间循环的 IGFBP-2b 和 IGF-1 介导一岁虹鳟鱼鳃 NKA 的大小依赖性激活。
Smoltification in salmonids occurs during spring in response to increasing photoperiod to prepare for marine life. Smoltification is associated with increased hypo-osmoregulatory ability and enhanced growth potential, mediated by growth hormone and insulin-like growth factor (IGF)-1. Rainbow trout is uniquely insensitive to the induction of smoltification-associated changes by photoperiod, such as the activation of gill Na+,K+-ATPase (NKA). We measured the circulating IGF-1 and IGF-binding protein (IGFBP)-2b levels in yearling rainbow trout exposed to natural and manipulated photoperiods during spring and correlated these with gill NKA activity and body size. Although the effect of photoperiod manipulation on body size and circulating IGF-1 and IGFBP-2b was negligible, they were positively correlated with gill NKA activity in fish under simulated natural photoperiod. We next pit-tagged yearling rainbow trout and fed them a restricted ration or to satiation under a natural photo period. In April, gill NKA activity was higher in the satiation group than in the restricted group and positively correlated with body size and growth rate. In addition, circulating IGFBP-2b was positively correlated with gill NKA, size and growth, whereas circulating IGF-1 was correlated only with size and growth. The relationship between circulating IGF-1 and growth intensified from May to June, suggesting that the IGF-1-growth relationship was disrupted in April when gill NKA was activated. Two additional IGFBPs were related to growth parameters but not to gill NKA activity. The present study suggests that circulating IGFBP-2b and IGF-1 mediate the size-dependent activation of gill NKA in yearling rainbow trout during spring.