Cousins K, Farrell A, Sweeting R, Vesely D, Keen J
J Exp Biol. 1997;200(Pt 9):1351-62. doi: 10.1242/jeb.200.9.1351.
Atrial natriuretic factor (ANF), a 28-amino-acid peptide hormone produced in the heart, circulates in both freshwater and seawater rainbow trout. In mammals, two other peptide hormones, proANF 1-30 and proANF 31-67, derived from the same 126-amino-acid prohormone as ANF (amino acids 99p;126), circulate and have natriuretic and diuretic properties. It has never been determined whether these peptides circulate in fish. The present investigation was designed to determine (1) whether proANF 1-30 and/or proANF 31-67 circulate in perfused hearts from freshwater- and seawater-acclimated rainbow trout (Oncorhynchus mykiss) in situ, and (2) if they do, to determine whether increasing the filling pressure of the heart causes their release in trout as it does in mammals. High-performance gel-permeation chromatography of fish plasma revealed that both proANF 1-30 and 31-67 circulate in freshwater- and seawater-acclimated trout plasma at threefold higher concentrations than does ANF. The basal rates of release of ANF and proANF 1-30 and 31-67 were similar in both freshwater and seawater trout, with the rate of release of proANF 1-30 being 10 times higher and that of proANF 31-67 20 times higher than that of ANF. When the filling pressure was increased to the peak of the Starling curve (max), the rate of release of ANF and proANFs 1-30 and 31-67 increased fivefold for each peptide in the freshwater trout, while in seawater trout the rates of release increased six- to ninefold. We conclude that proANF 1-30 and 31-67, as well as ANF, circulate in both freshwater-and seawater-acclimated trout and do so at concentrations higher than that of ANF. Increasing the filling pressure to the trout heart was found to cause a similar increase in the release rates for each of these peptides, but the maximal increase was higher in the seawater-acclimated trout, apparently because they showed a larger increase in cardiac output.
心房利钠因子（ANF）是一种由心脏产生的含28个氨基酸的肽类激素，在淡水和海水中的虹鳟体内均有循环。在哺乳动物中，另外两种肽类激素，即proANF 1 - 30和proANF 31 - 67，与ANF（氨基酸99 - 126）来源于同一含126个氨基酸的前体激素，它们在体内循环并具有利钠和利尿特性。鱼类体内是否存在这些肽类激素的循环尚未得到确定。本研究旨在确定：（1）proANF 1 - 30和/或proANF 31 - 67是否在原位灌流的淡水和海水驯化虹鳟（Oncorhynchus mykiss）心脏中循环；（2）如果存在循环，确定增加心脏充盈压是否会像在哺乳动物中那样导致虹鳟体内这些肽类激素的释放。对鱼血浆进行高效凝胶渗透色谱分析显示，proANF 1 - 30和31 - 67在淡水和海水驯化虹鳟的血浆中均有循环，其浓度比ANF高两倍。淡水和海水虹鳟体内ANF、proANF 1 - 30和31 - 67的基础释放速率相似，proANF 1 - 30的释放速率比ANF高10倍，proANF 31 - 67的释放速率比ANF高20倍。当充盈压增加到斯塔林曲线的峰值（max）时，淡水虹鳟体内ANF、proANF 1 - 30和31 - 67的释放速率均增加了五倍，而在海水虹鳟中，这些肽类激素的释放速率增加了六至九倍。我们得出结论，proANF 1 - 30和31 - 67以及ANF在淡水和海水驯化的虹鳟体内均有循环，且浓度高于ANF。研究发现，增加虹鳟心脏的充盈压会导致这些肽类激素的释放速率出现类似的增加，但在海水驯化虹鳟中的最大增加幅度更高，这显然是因为它们的心输出量增加幅度更大。
