Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gentamicin nephrotoxicity is associated with impairments in proximal tubular function. This study determined whether gentamicin administration to the rat, before a reduction in glomerular filtration rate (GFR), causes early and selective alterations in renal cortical brush-border membrane (BBM) enzyme and transport activity, lipid composition, and fluidity. Three days of gentamicin administration caused significant decreases in the Vmax of alkaline phosphatase, the Vmax of sodium gradient-dependent phosphate transport (Na-Pi cotransport), and the Vmax of pH gradient-dependent sodium transport (Na-H exchange). Gentamicin did not affect BBM-bound maltase or leucine aminopeptidase activities and sodium gradient-dependent glucose or proline transport activities. Gentamicin also caused a significant decrease in BBM sphingomyelin, significant increases in BBM phosphatidylcholine and phosphatidylinositol, a significant decrease in the phospholipid fatty acid saturation index, and a significant increase in BBM fluidity, i.e., decrease in the fluorescence anisotropy of diphenylhexatriene. These BBM functional and compositional effects of gentamicin were independent of endogenous parathyroid hormone activity. We conclude that gentamicin causes early and specific alterations in BBM enzyme and transport activity and also lipid composition, which may play an important role in the progression of renal cell injury.
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PMID:Early selective effects of gentamicin on renal brush-border membrane Na-Pi cotransport and Na-H exchange. 215 23

Cultured human renal cortical epithelial cells (NHK-C) were examined for functional and morphologic characteristics of the proximal tubule. Cultures were established by using cells isolated by progressive enzymatic dissociation from the extreme outer cortex of the normal human kidney. Cells were subcultured and used at passages 3 through 8. Cell uptake of alpha-methyl-D-glucoside (AMG), inorganic phosphate (Pi) and L-alanine was found to be dependent on the presence of Na+ in the incubation medium, and uptake increased with incubation time up to 30 minutes. Na+-dependent AMG uptake was inhibited 67% by phlorizin (1 mmol/L), and Pi uptake was inhibited 89% by parathyroid hormone (PTH) (10(-6) mol/L). Intracellular cyclic adenosine monophosphate was increased 28-fold after exposure to 10(-6) mol/L PTH but was increased only 2-fold by the same concentration of vasopressin. The cells exhibited endocytotic activity and possessed maltase, leucine aminopeptidase, and gamma-glutamyltranspeptidase, enzymes located exclusively in the brush border membranes of proximal tubule cells. NHK-C cultures were structurally heterogeneous, made up of a mixed-cell population with predominant epithelial-like morphology. Epithelial cells had cuboidal form, solitary cilia, and short, irregularly distributed apical microvilli. These cultures also formed multicellular hemicysts, but only through passage 3. NHK-C cultures showed a dramatic attenuation of proliferative activity at passages 8 through 10. These data show that subcultured cells derived from the outer cortex of the normal human kidney retain a number of functional characteristics typical of the proximal tubule.
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PMID:Proximal tubule characteristics of cultured human renal cortex epithelium. 253 26