Limas C, Limas C J
Am J Med Sci. 1985 Nov;290(5):185-91. doi: 10.1097/00000441-198511000-00002.
Renomedullary prostaglandin synthesis is lower in salt-sensitive (S) Dahl rats than in age-matched salt-resistant (R) rats on either 0.6% or 8.0% NaCl. The possible role of substrate availability to the cyclooxygenase in determining these differences was examined. S and R rats were started on diets with variable salt content (0.6%, 4.0% or 8.0% NaCl) at five weeks and were sacrified at either 11 or 16 weeks of age for comparisons of renomedullary phospholipase A1 and A2 activities (EC 3.1.1.4. and 3.1.1.32) and arachidonate incorporation into the lipids of renal medulla. Both phospholipase activities were higher in R rats at the two ages examined and for all levels of salt intake. These differences could not be accounted for by variable amounts of endogenous phospholipid substrate. High salt intake did not influence the in vitro A2 deacylating activities per mg protein. Arachidonate incorporation into renomedullary triglycerides remained constant with age in both strains while phospholipid labeling declined with age in S rats only so that, at 16 weeks of age, S rats had significantly lower incorporation into membrane phospholipids. This age-related decline in phospholipid labeling in S rats was prevented by 4.0% NaCl. These results suggest that low renomedullary phospholipase activities in S rats may restrict the release of substrate for prostaglandin synthesis and may also be related to reduced rates of fatty acid incorporation into membrane phospholipids.
在0.6%或8.0%氯化钠饮食条件下，盐敏感（S）Dahl大鼠的肾髓质前列腺素合成低于年龄匹配的盐抵抗（R）大鼠。研究了环氧化酶底物可用性在决定这些差异中的可能作用。S和R大鼠在5周龄时开始食用盐含量可变（0.6%、4.0%或8.0%氯化钠）的饮食，并在11周或16周龄时处死，以比较肾髓质磷脂酶A1和A2活性（EC 3.1.1.4和3.1.1.32）以及花生四烯酸掺入肾髓质脂质的情况。在所研究的两个年龄以及所有盐摄入水平下，R大鼠的两种磷脂酶活性均较高。这些差异不能用内源性磷脂底物量的变化来解释。高盐摄入不影响每毫克蛋白质的体外A2脱酰基活性。在两个品系中，花生四烯酸掺入肾髓质甘油三酯的量随年龄保持恒定，而仅在S大鼠中，磷脂标记随年龄下降，因此在16周龄时，S大鼠掺入膜磷脂的量显著降低。4.0%的氯化钠可防止S大鼠中与年龄相关的磷脂标记下降。这些结果表明，S大鼠肾髓质磷脂酶活性低可能会限制前列腺素合成底物的释放，也可能与脂肪酸掺入膜磷脂的速率降低有关。
