水钠负荷对血、肾脏前列环素、血栓素 A_2的影响及可能意义

EFFECT OF SALT-LOADING ON PROSTACYCLIN AND THROMBOXANE METABOLISM IN KIDNEY

本实验采用放射免疫方法测定盐负荷兔血浆及肾分层组织内6-酮-前列腺素 F_(1α)(6-kcto-PGF_(1α)、血栓素B_2(TXB_2),探讨前列环素、血栓素A_2在水盐平衡中的作用。结果表明;注射盐水后血浆及肾分层组织内6-keto-PGF_(1α)显著升高,内髓质 TXB_2 尿钠及滤过钠排泄分数均显著升高。血浆及肾组织6-keto-PGF_(1α),与尿钠排出量呈显著正相关。作者推测急性盐负荷能促进肾组织合成前列环素和血栓素 A_2的合成,两者在调节钠平衡中起重要作用。

For evaluating the role of prostacyclin(PGI_2)and thromboxane A_2(TXA_2)in the metabolism of salt and water,the metabolic products of PGI_2 and TXA_2(6-keto-PGF_(1α)and TXB_2 respectively)were measured by radioimmunoassay insalt-loaded rabbits.36 normal rabbits were randomly divided into 3 groups:1.normal control group;2.3h salt-loading group(3 h group);3.24 h salt-loadinggroup(24 h group).Both the 3 h and 24 h groups were given 0.9% NaCl solutionby subcutaneous injection to the hind legs.The kidneys were dissected into 4slices:outer cortex,inner cortex,outer medulla and inner medulla.The plasma6-keto-PGF_(1α)in the 3 h group was increased from the control value of 46.61±19.04pg/ml to 111.63±58.36 pg/ml(P<O. 01).All of the dissected renal slices also show-ed significant increase of 6-keto-PGF_(1α)synthesis in both the 3 h and the 24 h groups(P<0.001 vs.normal).The urinary sodium concentrations have a good correla-tion with 6-keto-PGF_(1α)in plasma or in kidney tissues.Plasma TXB_2 in normalgroup was 499.27±197.86 pg/ml,but no significant change was found in the3h group.However,in the 24 h group it decreased significantly to 218.76±114.54pg/ml(P<0.05 vs.normal group).Although the TXB_2 increment was significantonly in inner medulla,all other dissected renal slices showed some increase ofTXB_2,synthesis too.It is concluded that salt-loading can cause increase of PGI_1and TXA_2 synthesis in normal renal tissues.Both of the substances play importantroles in the balance of salt metabolism.