Torikai S, Kurokawa K
Miner Electrolyte Metab. 1984;10(1):21-5.
Effects of prostaglandins (PG) on intracellular cAMP content were examined in an intact cell preparation of single nephron segments dissected from rat kidney. PGE2 markedly increased cell cAMP in the thin descending limb of Henle (tDL) in a dose-dependent manner. Significant increases in cell cAMP were observed at 1-10 ng/ml PGE2, concentrations prevailing in the renal medulla in vivo, and the increase reached a maximum at a PGE2 concentration of 10 micrograms/ml. PGI2 also increased cell cAMP in the tDL, but the doses required were two orders of magnitude higher than those for PGE2. PGF2 alpha had only a minor effect, if any. PGE2 but not PGI2 also increased cell cAMP of rabbit tDL, but to a lesser magnitude than that seen in the rat tDL. PGE2 increase cell cAMP slightly in the cortical-collecting tubules at 10 micrograms/ml but no significant effect was seen in other nephron segments tested including proximal convoluted tubules, cortical and medullary thick ascending limbs of Henle, and medullary-collecting tubules. Results suggest a possible physiological effect of PGE2 via cAMP on the tDL thereby affecting the function of the renal medulla. Such an effect of PGE2 may underlie, at least in part, in the inhibition by PGE2 of vasopressin-mediated urinary concentration.
在从大鼠肾脏分离出的单个肾单位节段的完整细胞制剂中，研究了前列腺素（PG）对细胞内cAMP含量的影响。前列腺素E2（PGE2）以剂量依赖性方式显著增加亨利袢细降支（tDL）中的细胞cAMP。在1-10 ng/ml PGE2时观察到细胞cAMP显著增加，这是体内肾髓质中的普遍浓度，在PGE2浓度为10微克/毫升时增加达到最大值。前列环素（PGI2）也增加了tDL中的细胞cAMP，但所需剂量比PGE2高两个数量级。前列腺素F2α（PGF2α）即使有影响也很小。PGE2而非PGI2也增加了兔tDL中的细胞cAMP，但幅度小于大鼠tDL中的情况。PGE2在10微克/毫升时使皮质集合管中的细胞cAMP略有增加，但在其他测试的肾单位节段包括近端曲管、亨利袢皮质和髓质粗升支以及髓质集合管中未观察到显著影响。结果表明PGE2可能通过cAMP对tDL产生生理作用，从而影响肾髓质的功能。PGE2的这种作用可能至少部分是PGE对血管加压素介导的尿液浓缩的抑制作用的基础。
