Biochemical Correlations of Power Development and Metabolic Fuel Preferenda in Fish Hearts
Biochemical Correlations of Power Development and Metabolic Fuel Preferenda in Fish Hearts
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鱼心脏能量发展与代谢燃料偏好的生化相关性
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
I. Johnston
中科院分区：
文献类型：
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作者：
B. Sidell;W. Driedzic;D. Stowe;I. Johnston
对16种鱼类的心脏进行了研究，其中包括环口、棘鳃和硬骨鱼的代表。作为最大三磷酸腺苷需求量的生化指标，在优化肌原纤维活性和加入寡霉素抑制非生理性线粒体F-₁-ATPase的条件下，测定了心肌组织粗匀浆的ATPase活性。测定了来自能量代谢途径的另外九种酶的活性和肌红蛋白的浓度，肌红蛋白是一种参与氧气储存和扩散的细胞内蛋白质。在这些生化指标之间的所有可能的两两回归中，只有ATPase、肉碱棕榈酰转移酶(CPT)和己糖激酶(HK)以及HK与磷酸果糖激酶(PFK)之间的关系有显著意义。肌腱肌不能分解脂肪酸已得到证实。根据HK和CPT计算并经校正以反映组织的生理状况的ATP产量表明，碳水化合物或脂肪酸燃料的分解代谢可以满足组织的最大能量需求。虽然温带鱼类的心脏所包含的能量开发范围很大，但并没有导致选择性地扩大氧化一种特定代谢燃料的能力。
Hearts from 16 species of fishes, including representatives of cyclostomes, elasmobranchs, and teleosts, were examined. As a biochemical index of maximal ATP demand, ATPase activity of crude homogenates of ventricular tissue was measured under conditions which optimize activity of myofibrils and inhibit nonphysiological mitochondrial F₁-ATPase by inclusion of oligomycin in the assay medium. The activities of nine additional enzymes from pathways of energy metabolism and concentration of myoglobin-an intracellular protein involved in storage and diffusion of oxygen-were measured. Of all possible pairwise regressions between these biochemical markers, only the relationships among ATPase, carnitine palmitoyltransferase (CPT), and hexokinase (HK) and between HK and phosphofructokinase (PFK) were significant. The inability of elasmobranch myocardium to catabolize fatty acid is confirmed. ATP yields calculated from HK and CPT and corrected to reflect physiological conditions of the tissue suggest that catabolism of either carbohydrate or fatty acid fuels can meet maximal energetic demands of the tissue. The range of power developments encompassed by hearts of ectothermic fishes, although substantial, has not resulted in selective expansion of capacity to oxidize one particular metabolic fuel.