The absorption and excretion of water and salts by marine teleosts
The absorption and excretion of water and salts by marine teleosts
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DOI：
10.1152/ajplegacy.1930.93.2.480
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发表时间：
1930-06-01
影响因子：
--
通讯作者：
Breitweiser, A
中科院分区：
文献类型：
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作者：
Smith, HW;Farinacci, N;Breitweiser, A
它表明，海洋硬骨鱼吞下相对大量的海水，随后进行吸收。大部分摄入的水、Na、K和Cl从肠道吸收，留下富含Mg和SO4的残留物，与血液大致等渗。尿液中的盐主要由Mg和SO 4组成，只有微量的K和少量的Na和Cl，溶液与血液等渗或高渗。结果表明，肠道中Mg和SO_4来源于海水的摄入，而尿中Mg和SO_4来源于这些物质的消化吸收。通过对海水、肠道残留物和尿液成分的定量分析，得出以下结论：（1）海水中肠道残留物和尿液的渗透稀释性质表明，海水鱼在肾脏和胃肠道以外的某个部位进行渗透工作。2)Mg和SO 4在肠道残留物和尿液中的浓度高于摄入的海水（这些液体来自海水），这一事实表明，从消化道吸收的部分水通过肾脏以外的其他途径排出体外。从消化道吸收的Na、K和Cl比Mg和SO 4相对多，而从尿中排出的Na、K和Cl比Mg和SO 4少，这一事实表明，大部分吸收的NaCl和KCl通过肾脏以外的途径排出。通过将这3个过程视为一个过程，可以推断，海鱼通过某种肾外途径排泄NaCl和KCl溶液，该溶液对于摄入的海水是高渗的，因此留下部分吸收的水用于形成排泄稀释的尿液和肠残留物。通过向海水中加入酚红，并定量、同时测定在给定时间内摄入的水量和排泄的尿量，证明了安圭拉和Myoxocephalus的肾外排泄。肾脏外排泄的盐被证明在降河产卵鳗鱼，安圭拉，当保持在淡水中。从消化道吸收的大部分NaCl和KCl通过肾外途径排出，而基本上所有的Ca、Mg、SO 4和PO 4都通过肾脏排出。在没有其他盐的情况下，SO4带着Na进入尿液，Mg和Ca带着Cl。给出了相信盐和水的肾外排泄和渗透功的肾外表现归因于鳃的理由。淡水鱼的尿液不是从胃或肠吸收的，但可能是从口腔膜吸收的。海水鱼类的水循环是这样一种性质，即以尿液形式排泄的水量减少到淡水鱼类排泄水量的一小部分。这表明，这种相对无尿是一个明显的趋势，肾小球消失在严格的海洋硬骨鱼类的肾脏的主要致病因素。
It is shown that marine teleosts swallow relatively large quantities of sea water which subsequently undergoes absorption. Most of the ingested water, Na, K and Cl are absorbed from the intestine, leaving a residue rich in Mg and SO4 and approximately isotonic with the blood. The salts of the urine consist primarily of Mg and SO4, with only traces of K and small quantities of Na and Cl, the solution being isotonic or hypertonic to the blood. It is shown that the intestinal Mg and SO4 come from ingested sea water, and that the urinary Mg and SO4 come from alimentary absorption of these substances. Quantitative analysis of the composition of the ingested sea water, the intestinal residue and the urine lead to the following conclusions: 1) The os-motically dilute nature of the intestinal residue and urine elaborated from sea water shows that the marine fish is doing osmotic work at some point other than in the kidneys and gastro-intestinal tract. 2) The fact that Mg and SO4 occur in greater concentrations in both the intestinal residue and the urine than in the ingested sea water from which these fluids are derived shows that part of the water absorbed from the alimentary tract is excreted by some route other than the kidneys. The fact that relatively more Na, K and Cl are absorbed from the alimentary tract than Mg and SO4, while less Na, K and Cl are excreted in the urine than Mg and SO4 shows that a large part of the absorbed NaCl and KC1 is being excreted by some route other than the kidneys. By considering these 3 processes as identified with a single process, it is inferred that the marine fish excretes by some extrarenal route a solution of NaCl and KC1 which is hypertonic to the ingested sea water and thus leaves part of the absorbed water free for the formation of the osmotically dilute urine and intestinal residue. The extrarenal excretion of water is demonstrated in Anguilla and Myoxocephalus by the addition of phenol red to sea water and the quantitative, simultaneous determination of the quantity of water ingested and the quantity of urine excreted in a given time. The extrarenal excretion of salts is demonstrated in the catadromous eel, Anguilla, when kept in fresh water. The greater part of the NaCl and KCl absorbed from the alimentary tract is excreted by the extrarenal route, while essentially all the Ca, Mg, SO4 and PO4 are excreted by the kidneys. In the absence of other salts, SO4 takes Na into the urine with it, and Mg and Ca take Cl. Reasons are given for believing that the extrarenal excretion of salts and water and the extrarenal performance of osmotic work are attributable to the gills. The water for the formation of urine in fresh water fish is not absorbed from the stomach or intestine, but probably from the oral membranes. The water cycle in marine fish is of such a nature as to reduce the quantity of water excreted as urine to a small fraction of that excreted in fresh water fish. It is suggested that this relative anuria is the principal causative factor in an evident tendency for the glomeruli to disappear in the kidneys of strictly marine teleosts.