Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present studies were undertaken to determine, by recollection micropuncture, the effect of a synthetic atrial natriuretic peptide (ANP) on the absolute and fractional deliveries of water and sodium to the juxtamedullary end-descending limb. Two groups of young female Munich-Wistar rats were studied: control (n = 8) received the vehicle only; and ANP (n = 12) received a prime followed by the constant infusion of a synthetic rat atrial peptide (28 amino acids). With the infusion of ANP, clearance of p-[14C]aminohippurate [( 14C]PAH) and glomerular filtration rate (GFR) fell significantly. Despite this fall in GFR and renal plasma flow, ANP produced a 2-fold increase in urine volume and a 10-fold increase in sodium excretion. Absolute and fractional sodium deliveries to the end-descending limb increased by approximately 30% in the ANP group, whereas mean juxtamedullary single-nephron glomerular filtration rate (SNGFR) remained stable. In three additional rats prepared for micropuncture of the superficial end-accessible proximal tubule, ANP reduced cortical SNGFR by approximately 15%. By contrast, GFR did not decline in response to ANP in larger rats, when treated identically. We conclude that in young rats ANP can produce a natriuresis in the absence of a rise in GFR; the fall in GFR observed following ANP is due presumably to the immaturity of the animals used in these studies; and ANP produces a rise in absolute and fractional water and sodium deliveries to the end-descending limb that cannot be attributed to a change in SNGFR.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of synthetic ANP on renal and loop of Henle functions in the young rat. 294 65

The transport of ions and solutes at the epithelial surface of the renal proximal tubule increases during periods of reduced dietary intake and decreases with dietary excess. We have used the sulfur-containing beta-amino acid, taurine, as a probe of this renal adaptive response to altered dietary sulfur amino acid intake to better understand the mechanisms of renal amino acid reabsorption. There exists an age-related precession of taurine uptake values by brush border membrane vesicles prepared from nursing rats from youngest to oldest. However, despite the immaturity of this transport mechanism, epithelial membranes become able to display a full renal adaptive response to altered sulfur amino acid intake sometime between the 7th and 14th day of life. This adaptive response is expressed in both "up regulation" and "down regulation" by means of a change in the initial rate of Na(+)-taurine cotransport. No changes in the lipid microenvironment of the membrane, as assessed by measurements of membrane fluidity, are evident. The lack of adaptation observed in 7-day-old pups may be due to immaturity of the Na+ transporting mechanism which energizes the uptake of amino acids.
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PMID:Renal adaptation to dietary amino acid alteration is expressed in immature renal brush border membranes. 315 88

Differentiation of the glomerulus and the proximal tubule was studied in the rat foetus, especially with regard to the development of the protein filtration-reabsorption apparatus. Filtration starts several days before full differentiation of the glomerulus, when the glomerular basement membrane consists of a thin lamina alongside the podocyte membrane. Endocytosis is functional fom this time but fusion between endocytic vesicles and lysosome-like bodies occurs 2 days later. Foetal urine electrophoresis shows the presence of many proteins, including high molecular weight one, this proteinuria seeming chiefly due to the immaturity of the glomerular barrier.
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PMID:Differentiation of glomerular filter and tubular reabsorption apparatus during foetal development of the rat kidney. 744 Nov 51

Renal tubular dysgenesis is a rarely recognized condition characterized by oligohydramnios, Potter's sequence and congenital anuria leading to stillbirth or neonatal death from respiratory failure. It is thought to be inherited in an autosomal recessive manner. Definitive diagnosis is based on renal histology, revealing the lack of proximal tubule differentiation. Two additional cases of affected sibs in a family with parental consanguinity are reported. Lectin and immunohistochemical studies confirmed structural and functional immaturity of the proximal tubule. Further findings include bilateral renal vein thrombosis. The clinical and morphological parameters defining this disorder and the possible mechanisms of pathogenesis are discussed.
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PMID:[Renal tubular dysgenesis with fetal renal vein thrombosis]. 776 60