Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1332347 (ADH)
 2,230 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

High protein diet is known to increase glomerular filtration rate (GFR) and induce kidney hypertrophy. The mechanisms underlying these changes are not understood. Since the mammalian kidney comprises different nephron segments located in well-delineated zones, it is conceivable that the hypertrophy does not affect all kidney zones and all nephron segments uniformly. The present experiments were designed to study the chronic effects of high or low isocaloric protein diets (HP = 32% or LP = 10% casein, respectively) on kidney function and morphology in Sprague-Dawley rats. HP diet induced significant increases in kidney mass, GFR, free water clearance, and maximum urine concentrating ability. Kidney hypertrophy was characterized by: 1. a preferential 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 marked hypertrophy of the thick ascending limbs (TAL) in the inner stripe (+40% epithelium volume/unit tubular length, P less than 0.05) but not in the outer stripe nor in the cortex; 3. an increase in heterogeneity of glomeruli between superficial (S) and deep (D) nephrons (D/S = 1.47 in HP vs. 1.17 in LP, P less than 0.05). In contrast, normal kidney growth with age and kidney hypertrophy induced by uninephrectomy were not accompanied by preferential enlargement of IS structures. The morphologic changes induced by high protein intake parallel those we previously reported in rats fed a normal diet (25% protein) but in which the operation of the urine concentrating mechanism was chronically stimulated by ADH infusion or by reduction in water intake.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of the urinary concentrating process in the renal effects of high protein intake. 317 35

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)
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PMID:Possible role of the thick ascending limb and of the urine concentrating mechanism in the protein-induced increase in GFR and kidney mass. 348 Sep 97