Morris B J
Department of Physiology, University of Sydney, New South Wales, Australia.
Am J Physiol. 1988 Sep;255(3 Pt 1):E353-6. doi: 10.1152/ajpendo.1988.255.3.E353.
To test directly the possibility that substances in extracellular fluid can gain access to renin storage granules in renal juxtaglomerular cells, rats were injected with Triton WR-1339, which binds to plasma proteins. A heavy granule fraction was prepared, and isopycnic sucrose density gradient centrifugation was performed. The renin granule peak was found to be altered from a mean equilibrium density of 1.202 g/ml in control rats to 1.196 g/ml for rats injected with Triton WR-1339 (P less than 0.005). The distribution of angiotensinogen, which is bound in kidney granules having a different buoyant density, was also examined and found to be unaltered. After injection, Triton WR-1339 binds to circulating plasma proteins. The results for renin support the possibility of pinocytotic uptake of protein-Triton WR-1339 complexes by the juxtaglomerular cells with subsequent fusion of the endocytotic lysosomal vacuoles with renin granules accounting for the translocation of ingested substances into the granule matrix. If so, the potential would therefore exist for interaction(s) of ingested extracellular substances with renin or other components in the granules. The present study has therefore demonstrated directly that endogenous extracellular substances may enter renin granules.
为了直接验证细胞外液中的物质能够进入肾球旁细胞中肾素储存颗粒的可能性，给大鼠注射了与血浆蛋白结合的曲拉通WR - 1339。制备了重颗粒组分，并进行了等密度蔗糖密度梯度离心。发现肾素颗粒峰的平均平衡密度从对照大鼠的1.202 g/ml变为注射曲拉通WR - 1339的大鼠的1.196 g/ml（P小于0.005）。还检查了结合在具有不同浮力密度的肾颗粒中的血管紧张素原的分布，发现其未改变。注射后，曲拉通WR - 1339与循环血浆蛋白结合。肾素的结果支持球旁细胞对蛋白 - 曲拉通WR - 1339复合物进行胞饮摄取的可能性，随后内吞溶酶体空泡与肾素颗粒融合，这解释了摄入物质向颗粒基质的转运。如果是这样，那么摄入的细胞外物质就有可能与颗粒中的肾素或其他成分发生相互作用。因此，本研究直接证明了内源性细胞外物质可能进入肾素颗粒。
