Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, Chiba 277-8564, Japan.
Gen Comp Endocrinol. 2011 May 1;171(3):258-66. doi: 10.1016/j.ygcen.2011.02.021. Epub 2011 Mar 22.
The natriuretic peptide (NP) family consists of at least seven members; cardiac ANP, BNP and VNP and brain CNPs (CNP1-4). Phylogenetic and comparative genomic analyses showed that CNP4 is the ancestral molecule of the family, from which CNP3 and CNP1/2 were duplicated in this order, and that the three cardiac NPs were generated from CNP3 by tandem duplication. Seven members existed at the divergence of ray-finned fishes and lobe-finned fishes (tetrapods), but some of the NP genes have disappeared during the course of evolution. In ray-finned fishes, all three cardiac NPs exist in chondrostei and some migratory teleost species, but VNP is generally absent and ANP is absent in a group of teleosts (Beloniformes). In tetrapods, ANP and BNP are present in mammals and amphibians, but ANP is usually absent in reptiles and birds. Thus, BNP is a ubiquitous cardiac NP in bony fishes and tetrapods though elasmobranchs and cyclostomes have only CNP3/4 as a cardiac NP. Functional studies indicate that cardiac NPs are essential Na(+)-extruding hormones throughout vertebrates; they play critical roles in seawater (SW) adaptation in teleosts, while they are important volume-depleting hormones in mammals as water and Na(+) are regulated in parallel in terrestrial animals. In mammals, cardiac NPs become prominent in pathological conditions such as heart failure where they are used in diagnosis and treatment. Although the functional role of BNP has not yet been fully elucidated compared with ANP in non-mammalian vertebrates, it appears that BNP plays pivotal roles in the cardiovascular and body fluid regulation as shown in mammals. ANP has previously been recognized as the principal cardiac NP in mammals and teleosts, but comparative studies have revealed that BNP is the only cardiac NP that exists in all tetrapods and teleosts. This is an excellent example showing that comparative studies have created new insights into the molecular and functional evolution of a hormone family.
利钠肽（NP）家族至少由 7 种成员组成；心脏的 ANP、BNP 和 VNP 以及脑 CNP（CNP1-4）。系统发生和比较基因组分析表明，CNP4 是该家族的原始分子，CNP3 和 CNP1/2 依次从该分子复制而来，而这三种心脏 NPs 则是通过串联复制从 CNP3 产生的。在射线鳍鱼类和肺鱼（四足动物）的分歧中存在 7 种成员，但在进化过程中，一些 NP 基因已经消失。在射线鳍鱼类中，所有三种心脏 NPs 都存在于软骨鱼类和一些洄游性硬骨鱼类中，但 VNP 通常不存在，而 ANP 则不存在于一组硬骨鱼类（鲈形目）中。在四足动物中，ANP 和 BNP 存在于哺乳动物和两栖动物中，但在爬行动物和鸟类中通常不存在 ANP。因此，BNP 是硬骨鱼类和四足动物中普遍存在的心脏 NP，尽管软骨鱼类和圆口类只有 CNP3/4 作为心脏 NP。功能研究表明，心脏 NPs 是整个脊椎动物中必不可少的排钠激素；它们在硬骨鱼类的海水（SW）适应中发挥关键作用，而在哺乳动物中，它们是重要的容积耗竭激素，因为在陆生动物中，水和 Na+是平行调节的。在哺乳动物中，心脏 NPs 在心力衰竭等病理条件下变得突出，在这些情况下，它们被用于诊断和治疗。尽管与非哺乳动物脊椎动物中的 ANP 相比，BNP 的功能作用尚未完全阐明，但似乎 BNP 像在哺乳动物中一样，在心血管和体液调节中发挥关键作用。ANP 以前被认为是哺乳动物和硬骨鱼类的主要心脏 NP，但比较研究表明，BNP 是唯一存在于所有四足动物和硬骨鱼类中的心脏 NP。这是一个极好的例子，表明比较研究为激素家族的分子和功能进化提供了新的见解。
