Kapoor S C, Krishna G P
Renal Electrolyte Section, University of Pennsylvania, Philadelphia 19104.
Am J Kidney Dis. 1993 Apr;21(4):363-7. doi: 10.1016/s0272-6386(12)80261-7.
Previous studies from our and other laboratories demonstrated that dietary protein restriction lowers plasma renin activity by impairing renin release. The effect of protein intake on glomerular renin secretion has not been investigated. Accordingly, we studied male Sprague-Dawley rats weighing 180 to 200 g for 3 weeks that were receiving isocaloric diets that provided either standard 20% protein (SP) or low 6% protein (LP). Renin secretion was measured in the glomeruli isolated from these rats, at baseline and following stimulation with arachidonic acid and isoproterenol. The activity of plasma renin (3.0 +/- 0.5 ng/mL/min on SP v 1.1 +/- 0.1 ng/mL/min on LP) was significantly (P < 0.02) lower on LP intake. In contrast, glomerular renin content (22.9 +/- 0.7 ng/micrograms protein on SP v 32.3 +/- 1.4 ng/micrograms protein on LP) was significantly (P < 0.01) higher on the LP diet. Furthermore, renin secretion (ng/mL/h) from the isolated glomeruli at baseline (3.9 +/- 1.0 on SP v 12.5 +/- 3.0 on LP, P < 0.02), and following incubation with arachidonic acid 10(-5) mol/L (5.9 +/- 1.7 on SP v 19.6 +/- 3.1 on LP, P < 0.005), and isoproterenol 10(-3) mol/L (6.0 +/- 0.5 on SP v 17.3 +/- 3.3 on LP, P < 0.01) was significantly higher on the LP diet. These studies suggest that dietary protein restriction impairs in vivo renin release. In contrast, in vitro glomerular renin release is augmented by protein restriction. The factors modulating in vivo renin release require further characterization.
我们实验室及其他实验室先前的研究表明，饮食中蛋白质限制会通过损害肾素释放来降低血浆肾素活性。蛋白质摄入量对肾小球肾素分泌的影响尚未得到研究。因此，我们对体重180至200克的雄性斯普拉格 - 道利大鼠进行了为期3周的研究，这些大鼠接受等热量饮食，分别提供标准的20%蛋白质（SP）或低含量的6%蛋白质（LP）。在基线以及用花生四烯酸和异丙肾上腺素刺激后，测量从这些大鼠分离出的肾小球中的肾素分泌。血浆肾素活性（SP组为3.0±0.5纳克/毫升/分钟，LP组为1.1±0.1纳克/毫升/分钟）在LP饮食时显著降低（P<0.02）。相反，LP饮食时肾小球肾素含量（SP组为22.9±0.7纳克/微克蛋白质，LP组为32.3±1.4纳克/微克蛋白质）显著升高（P<0.01）。此外，在基线时，分离出的肾小球的肾素分泌（纳克/毫升/小时）（SP组为3.9±1.0，LP组为12.5±3.0，P<0.02），以及与10⁻⁵摩尔/升花生四烯酸孵育后（SP组为5.9±1.7，LP组为19.6±3.1，P<0.005）和与10⁻³摩尔/升异丙肾上腺素孵育后（SP组为6.0±0.5，LP组为17.3±3.3，P<0.01），LP饮食时均显著更高。这些研究表明，饮食中蛋白质限制会损害体内肾素释放。相反，蛋白质限制会增强体外肾小球肾素释放。调节体内肾素释放的因素需要进一步表征。
