Cholesterol affects physical properties and (Na+,H+)-ATPase in basolateral membranes of renal and intestinal epithelia from thermally acclimated rainbow trout
Cholesterol affects physical properties and (Na+,H+)-ATPase in basolateral membranes of renal and intestinal epithelia from thermally acclimated rainbow trout
复制标题
DOI：
10.1007/s003600050083
复制
发表时间：
1997-07-01
期刊：
影响因子：
--
通讯作者：
Hazel, JR
中科院分区：
文献类型：
--
作者：
Crockett, EL;Hazel, JR
先前的工作表明，胆固醇水平在变温动物的一些但不是所有组织的质膜中随温度变化而调节。为了更好地了解组织和膜结构域特异性胆固醇功能在热适应过程中，我们研究了胆固醇对膜物理性质和（Na+，K+）-ATP酶的影响，在本地和胆固醇富集的基底外侧膜从肾脏和肠的热驯化鳟鱼（虹鳟鱼mykiss）。膜顺序（如荧光去极化研究所示）增加，而其热敏感性降低胆固醇水平升高的膜与相对较低的内源性量的胆固醇（肠膜和肾膜冷驯化鱼）。与富含胆固醇的基底外侧膜相比，肾脏中膜顺序的热敏感性高1.5倍。对于肾质膜，（Na+，K+）-ATP酶活性在天然胆固醇水平和超生理胆固醇水平之间的过渡附近最低。内源性胆固醇水平（相对于磷脂含量）在肠基底外侧膜从冷驯化的鱼变化超过1.5倍;膜胆固醇/磷脂摩尔比为0.3的活性（Na+，K+）-ATP酶是两倍低于天然膜的比例为0.2。这些结果表明，在热习服过程中，肠基底外侧膜胆固醇水平的维持可能确保足够的（Na+，K+）-ATP酶的活性。肾脏的膜功能，由于其天然胆固醇含量高，不太可能受到温度变化的影响。
Previous work has shown that cholesterol levels are modulated in plasma membranes from some but not all tissues of poikilotherms over the course of temperature change. To gain a better understanding of tissue and membrane domain-specific cholesterol function during thermal adaptation we examined effects of cholesterol on membrane physical properties and (Na+,K+)-ATPase in native and cholesterol-enriched basolateral membranes from kidney and intestine of thermally acclimated trout (Oncorhynchus mykiss). Membrane order (as indicated by fluorescence depolarization studies) is increased, whereas its thermal sensitivity is decreased by elevated cholesterol levels in membranes with relatively low endogenous amounts of cholesterol (intestinal membranes and renal membranes from cold-acclimated fish). Thermal sensitivities of membrane order in kidney are 1.5-fold higher in native compared with cholesterol-enriched basolateral membranes. For renal plasma membranes, (Na+,K+)-ATPase activity is lowest near the transition between native and surpraphysiological cholesterol levels. Endogenous cholesterol levels (relative to phospholipid contents) in intestinal basolateral membranes from cold-acclimated fish vary more than 1.5-fold; membranes with cholesterol/phospholipid molar ratios of 0.3 have activities of (Na+,K+)-ATPase that are twofold lower than native membranes having a ratio of 0.2. These results suggests that maintenance of cholesterol levels in intestinal basolateral membranes during thermal acclimation may ensure sufficient activity of (Na+,K+)-ATPase. Membrane function in kidney, with its high native cholesterol content, is less likely to be affected by temperature change.