Bouby N, Trinh-Trang-Tan M M, Kriz W, Bankir L
INSERM. U. 90, Department of Nephrology, Hôpital Necker, Paris, France.
Kidney Int Suppl. 1987 Oct;22:S57-61.
The mechanisms by which high protein intake increases filtration rate and kidney hypertrophy in health and may be detrimental to the kidney in chronic renal failure are not well understood. We studied the kidneys of Sprague Dawley rats fed high (HP) and low (LP) isocaloric protein diets (32% and 10% casein, respectively) for 4 weeks. HP induced significant increases in kidney mass, GFR, and maximum urine concentrating ability (UMax). Kidney hypertrophy was characterized by (1) a selective increase in thickness of the inner stripe of the outer medulla (IS, +54%, P less than 0.001) while total kidney height (from cortex to papillary tip) increased only by 18%; (2) a considerable hypertrophy of the thick ascending limbs (TAL) in the IS (+43% epithelium volume/unit tubular length) but not in the outer stripe nor in the cortex; and (3), an increase in heterogeneity of glomerular volume between superficial and deep nephrons (P less than 0.05). these morphologic changes parallel those we previously reported in rats fed a normal protein diet (25% casein) but in which the operation of the urine concentrating mechanism was chronically stimulated by ADH infusion or by reduction in water intake. In contrast, normal kidney growth with age or kidney hypertrophy induced by uninephrectomy were not accompanied by preferential enlargement of IS structures.(ABSTRACT TRUNCATED AT 250 WORDS)
高蛋白摄入在健康状态下增加滤过率和导致肾脏肥大，而在慢性肾衰竭时可能对肾脏有害，其机制尚未完全明确。我们研究了分别喂食高（HP）、低（LP）等热量蛋白质饮食（分别为32%和10%酪蛋白）4周的Sprague Dawley大鼠的肾脏。HP导致肾脏重量、肾小球滤过率（GFR）和最大尿浓缩能力（UMax）显著增加。肾脏肥大的特征为：（1）外髓质内带（IS）厚度选择性增加（+54%，P<0.001），而肾脏总高度（从皮质到乳头尖端）仅增加18%；（2）IS中厚壁升支（TAL）显著肥大（上皮细胞体积/单位肾小管长度增加43%），但在外带和皮质中未出现；（3）浅表和深部肾单位之间肾小球体积的异质性增加（P<0.05）。这些形态学变化与我们之前报道的喂食正常蛋白质饮食（25%酪蛋白）的大鼠相似，但在这些大鼠中，尿浓缩机制的运作通过输注抗利尿激素或减少水摄入而受到慢性刺激。相比之下，正常的随年龄增长的肾脏生长或单侧肾切除引起的肾脏肥大并未伴有IS结构的优先增大。（摘要截断于250字）
