Spangler W L
Am J Vet Res. 1979 Jun;40(6):809-9.
Pathophysiologic changes in the juxtaglomerular apparatus (JGA) of the dog were induced by 10 days of dietary sodium restriction (less than 1 mEq of Na+/day). Plasma renin activity increased 12-fold and plasma aldosterone values increased 60-fold, whereas urinary sodium excretion decreased precipitously. Urinary potassium excretion remained within normal values throughout the period of sodium restriction. The JGA cell counts, determined by light microscopy, were significantly (P = less than 0.05) increased after 2 days of sodium restriction and remained increased through day 10. Adrenal gland weights and the cross-sectional width of the zona glomerulosa were not altered. Ultrastructurally, JGA cells showed progressive hypertrophy and hyperplasia. The Golgi apparatus became more prominent. The endoplasmic reticulum increased, as did the number of ribosomes. Cytoplasmic secretory granules increased in number and size from day 2 through day 6. On days 8 and 10, fewer and smaller secretory granules were encountered, even though plasma renin and aldosterone values continued to increase. In the dog maintained in a balanced sodium state, little renin is stored in cytoplasmic granules of the juxtaglomerular cells. Short-term stimulation results in increased plasma renin values and increased production and storage of renin in JGA cells. Continued stimulation results in depletion of cytoplasmic stores, although plasma renin content continues to rise, suggesting that renin is produced and secreted directly during more prolonged stimulation.
通过10天的饮食限钠（每天少于1 mEq的Na +）诱导狗肾小球旁器（JGA）的病理生理变化。血浆肾素活性增加了12倍，血浆醛固酮值增加了60倍，而尿钠排泄急剧下降。在限钠期间，尿钾排泄一直保持在正常值范围内。通过光学显微镜确定的JGA细胞计数在限钠2天后显著增加（P <0.05），并在第10天一直保持增加。肾上腺重量和球状带的横截面积没有改变。超微结构上，JGA细胞呈现进行性肥大和增生。高尔基体变得更加突出。内质网增加，核糖体数量也增加。从第2天到第6天，细胞质分泌颗粒的数量和大小增加。在第8天和第10天，尽管血浆肾素和醛固酮值继续增加，但遇到的分泌颗粒越来越少且越来越小。在维持钠平衡状态的狗中，肾小球旁细胞的细胞质颗粒中几乎没有储存肾素。短期刺激导致血浆肾素值增加以及JGA细胞中肾素的产生和储存增加。持续刺激导致细胞质储存耗尽，尽管血浆肾素含量继续上升，这表明在更长时间的刺激过程中肾素是直接产生和分泌的。
