The Biology of Glycerol-Producing Arctic Fishes

许多极地鱼类产生大分子防冻剂，这种防冻剂以非综合方式起作用，防止结冰。斯库尔特和格林林科的一些北极鱼使用一种新的方法来避免冰冻。这些鱼在冬天会产生高浓度的甘油，从而增加体液的冰点降幅。这项研究将集中在北极鱼类中甘油的高浓度及其对水平衡、肾和鳃功能以及能量储存代谢的生理生化影响。将通过测量肾小球滤过率、尿流量、饮酒率和鳃对甘油的渗透率来调查肾脏和鳃对甘油的保存情况。由于甘油只在冬季存在，这些参数的季节变化将被确定。甘油的来源和去向将通过对冷驯鱼和温驯鱼的糖原、脂肪和关键酶的分析来确定。还将进行其他研究，以确定冷驯化鱼类中甘油的最大浓度，调节其生产的环境条件，以及甘油在其他物种中的出现情况。熔炼的一个令人费解的特点是，它们既有综合防冻剂，也有非综合防冻剂。将进行进一步的研究，以解释为什么这些物种需要两种不同的防冻剂。

Many polar fishes produce macromolecular antifreezes that act in non-colligative way to prevent freezing. Some arctic fishes in the Smelt and Greenling families use a novel method to avoid freezing. These fishes increase the freezing point depression of their body fluids by producing high concentrations of glycerol in winter. This study will focus on the high glycerol concentrations in arctic fishes and the physiological and biochemical implications they have on water balance, kidney and gill function, and metabolism of energy stores. Conservation of glycerol by the kidney and gills will be investigated by measuring glomerular filtration rate, urine flow, drinking rate and permeability of the gills to glycerol. Because glycerol is present only in winter, seasonal variations in these parameters will be determined. The source and fate of glycerol will be determined with assays of glycogen, lipid and key enzymes using cold- and warm-acclimated fish. Additional studies will be conducted to determine the maximum concentrations of glycerol that occur in cold-acclimated fishes, the environmental conditions that regulate its production, and the occurrence of glycerol in other species. A puzzling characteristic of the smelts is that they have both colligative and non-colligative antifreezes. Further studies will be undertaken to explain why two different antifreezes are needed in these species.