Gerbi A, Zerouga M, Debray M, Durand G, Chanez C, Bourre J M
INSERM U26 Hôpital Fernand Widal, Paris, France.
Biochim Biophys Acta. 1993 Jan 10;1165(3):291-8. doi: 10.1016/0005-2760(93)90139-z.
The influence of dietary fatty acids on Na+ sensitivity and ouabain affinity of Na+/K(+)-ATPase isoenzymes of whole brain membranes were studied in weaned rats fed for two generations with diets either devoid of alpha-linolenic acid (sunflower oil diet) or rich in alpha-linolenic acid (soya oil diet). The (n--3) deficiency induced by the sunflower oil diet led to an increase in the (n--6)/(n--3) molar ratio in whole brain membranes. Na+/K(+)-ATPase isoenzymes were discriminated on the basis of their differential affinities for ouabain. In rats fed sunflower oil diet, the ouabain titration displayed three inhibitory processes with markedly different affinities: low affinity (alpha 1); high affinity (alpha 2); and very high affinity (alpha 3). Membranes of rats fed soya oil diet exhibited only two inhibitory processes, i.e., low affinity (likely alpha 1+ alpha 2) and high affinity (likely alpha 2+ alpha 3) with the low affinity form intermediate between the sunflower alpha 1 and alpha 2 forms, and the high affinity form intermediate between the sunflower alpha 2 and alpha 3 forms. In fact, the Na+ response shows that the three isoenzymes have different Na+ sensitivities. Regardless of the diet, alpha 1 has a similar Na+ sensitivity (less than 1 mM), whilst alpha 2 and alpha 3 are more sensitive in soya oil membranes compared to sunflower oil membranes (5.1 vs. 7.2 mM and about 11 vs. 22.5 mM, respectively). Thus, sodium appears to be a better criterion of heterogeneity than ouabain.
在断乳大鼠中研究了膳食脂肪酸对全脑膜Na⁺/K⁺-ATP酶同工酶的Na⁺敏感性和哇巴因亲和力的影响，这些大鼠两代都喂食缺乏α-亚麻酸的日粮（葵花籽油日粮）或富含α-亚麻酸的日粮（大豆油日粮）。葵花籽油日粮引起的(n-3)缺乏导致全脑膜中(n-6)/(n-3)摩尔比增加。根据Na⁺/K⁺-ATP酶同工酶对哇巴因的不同亲和力来区分它们。喂食葵花籽油日粮的大鼠，哇巴因滴定显示出三个亲和力明显不同的抑制过程：低亲和力(α1)；高亲和力(α2)；和非常高亲和力(α3)。喂食大豆油日粮的大鼠的膜仅表现出两个抑制过程，即低亲和力（可能是α1+α2）和高亲和力（可能是α2+α3），低亲和力形式介于葵花籽α1和α2形式之间，高亲和力形式介于葵花籽α2和α3形式之间。事实上，Na⁺反应表明这三种同工酶具有不同的Na⁺敏感性。无论日粮如何，α1具有相似的Na⁺敏感性（小于1 mM），而与葵花籽油膜相比，α2和α3在大豆油膜中更敏感（分别为5.1对7.2 mM和约11对22.5 mM）。因此，钠似乎比哇巴因是更好的异质性标准。
