Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pulmonary toxicity of zinc oxide (ZnO) was evaluated by investigating the metabolic fate and inflammatory potency of ZnO instilled into the rat lung. Groups of three rats received single intratracheal instillations of ZnO suspension at a dose of 100 micrograms Zn/rat in the time-course experiment or received 20, 50, 100, 200, 500 and 1000 micrograms Zn/rat and were killed 2 days after treatment in the dose-response experiment. It was suggested that ZnO particles were solubilized in the bronchoalveolar milieu and cleared from the lung with a half-life of 14 h. Metallothionein (MT) was induced with a peak at 2 days. The content of MT was proportional to the dose of ZnO, but contributed little for the accumulation of Zn in the lung. A dose of 20 micrograms Zn/rat was sufficient to develop maximum responses for beta-glucuronidase activity and surfactant content in the bronchoalveolar lavage fluid. Moreover, the activity of lactate dehydrogenase and protein content in the lavage fluid increased significantly at 20 micrograms Zn/rat. These results suggest that the recommended ZnO concentration in the work-place atmosphere of 5 mg/m3 might not be adequate.
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PMID:Pulmonary clearance and toxicity of zinc oxide instilled into the rat lung. 276 23

Cellular biomarkers of exposure and biological effects were measured in hepatocytes of turbot exposed to either Cd, Cu or Zn at concentrations of 1 and 10 mg/l seawater for 7 days and after depuration for 14 days. Metal content in hepatocyte lysosomes was determined by image analysis after autometallography (AMG) as volume density of autometallographed black silver deposits (Vv(BSD)). Metallothionein (MT) levels were quantified on liver sections by microdensitometry after immunohistochemical staining with a polyclonal anti cod-MT antibody (MT-OD), and in the cytosolic fraction of hepatocytes by difference pulse polarography (MT-DPP). Lysosomal structural changes (lysosomal volume, surface and numerical densities--Vv(LYS), Sv(LYS) and Nv(LYS-), and surface-to-volume ratio S/V(Lys)) were quantified by image analysis after demonstration of beta-glucuronidase activity on liver cryotome sections. Vacuolisation produced by metal-exposure in hepatocytes was quantified by stereology as volume density of vacuoles (Vv(VAC)). Exposure time and metal concentrations significantly affected Vv(BSD) in lysosomes, MT levels and the degree of vacuolisation after 1 h and 1 day exposure to the three metals. The highest Vv(BSD), MT and Vv(VAC) values were recorded after 7 days exposure in all cases. MT-OD and MT-DPP were significantly correlated with Vv(BSD). Vv(LYS) in hepatocytes increased significantly after exposure to the metals. Exposure biomarkers returned to control values after depuration with the exception of those turbots that had been exposed to 10 mg Cd/l. Alike, Vv(LYS) and Sv(lys) (Cu exposure) and Nv(LYS) (Cd and Zn exposures) returned to control values after depuration. It has been therefore demonstrated that the biomarkers used are reversible and return towards control levels once metal exposure ceases. Overall, it is concluded that Vv(BSD), MT-levels and lysosomal responses are valuable biomarkers to assess metal exposure and its effects in turbot, although in quantitative terms the biomarker response varied between metals.
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PMID:Cellular biomarkers of exposure and biological effect in hepatocytes of turbot (Scophthalmus maximus) exposed to Cd, Cu and Zn and after depuration. 1599 Jan 79