The effect of dexamethasone (10(-5)M) and epinephrine (10(-6)M) on the biosynthesis of metallothionein (MT) in the perfused rat liver was investigated. MT synthesis was determined by measuring the incorporation of 14C-L-aspartic acid into liver MT fraction after the perfusion for five hours of isolated liver by artificial blood containing 14C-L-U-aspartic acid (0.2uci) with dexamethasone or epinephrine. MT was isolated by Sephadex G-75 column chromatography and DEAE Sephadex column chromatography. Incorporation of radioactive 14C into the MT fraction of perfused liver cytosol (9.0grams of liver) from dexamethasone treated, epinephrine treated and control groups were, respective1y, 0.72, 0.34 and 0.33% of total radioactivity infused. Total protein content in the MT fraction of liver perfused with dexamethasone and epinephrine were 0.80, 0.64mg/g liver compared to 0.52mg/g liver in the control. MT, a protein having a high content of cystein and metals is synthesized in the perfused rat liver and its induction is stimulated by dexamethasone, while epinephrine increased the accumulation of Zn in the MT fraction of the perfused rat liver. The present experiment confirms that MT synthesis and degradation are somewhat regulated by glucocorticoid hormone and epinephrine.
Animal ; Dexamethasone/pharmacology* ; Epinephrine/pharmacology* ; Female ; In Vitro ; Liver/drug effects ; Liver/metabolism* ; Metalloproteins/metabolism* ; Metallothionein/metabolism* ; Perfusion ; Rats ; Zinc/metabolism

Homocysteine ; pharmacology ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Lipid Peroxidation ; drug effects ; Metallothionein ; pharmacology

Metallothioneins (MT), small molecular weight metal binding proteins are known to play an important protective role against heavy metal toxicity, either as antioxidants or pre-oxidants. However, the mode of metabolic fate of MTs in various metal complexes is not clearly understood. This study was carried out to better understand the mode of selective turnover rate of various form of MT in complexes with different metals. The degradation of in vitro translated mouse 35S-cysteine-MT was examined in lysosomal or cytosolic fractions from mouse liver by gel electrophoresis and autoradiography. Overnight incubations of MT showed extensive proteolysis in the lysosomal fraction but not in cytosolic fractions. However, Cu2+-MT was found to be stable under the same experimental condition. In contrast, Zn did not interfere with MT degradation. These results suggest that lysosomes are chiefly responsible for MT removal and appears to be selective on the metals involved in the MT complex. In vitro, translated, radiolabeled MT provides a suitable substrate for investigating the characteristics of MT degradation.
Animal ; Copper/*metabolism/pharmacology ; Ions ; Liver/drug effects/*metabolism ; Lysosomes/metabolism ; Metallothionein/drug effects/*metabolism ; Mice ; Sulfur Radioisotopes ; Support, Non-U.S. Gov't ; Zinc/*metabolism/pharmacology

OBJECTIVE[corrected] To assess the effects of metallothionein on myocyte apoptosis and energy supply of isolated rabbit heart muscle during perfusion with ropivacaine..

METHODSSixty New Zealand white male rabbits were randomized into 3 equal groups. In group I, the rabbits received a intreaperitioneal injection of distilled water 24 h before isolation of the heart with perfusion by Langendoff model; in group II, distilled water was injected intreaperitioneally, and 24 h later the heart was isolated and perfused with Langendoff model and ropivacaine; in group III, 3.6% ZnSO(4) was injected intreaperitioneally and the isolated heart was perfused with Langendoff model and ropivacaine. The myocardial metallothionein content, myocyte apoptosis, and myocardial ATP, ADP and AMP content were detected.

RESULTSThe myocardial metallothionein content was significantly higher in group III than in the other two groups; the percent of myocyte apoptosis was the highest in group II, and was significantly higher in group III than in group I. The myocardial content of ATP was the highest in group I, and was significantly higher in group III than in group II.

CONCLUSIONMetallothionein can significantly inhibit myocyte apoptosis and alleviate energy supply disorder induced by ropivacaine.

Amides ; pharmacology ; Animals ; Apoptosis ; drug effects ; Energy Metabolism ; drug effects ; In Vitro Techniques ; Male ; Metallothionein ; pharmacology ; Myocardium ; cytology ; metabolism ; Myocytes, Cardiac ; cytology ; metabolism ; Perfusion ; Rabbits

OBJECTIVETo study the possible intervention of isoflavones in cytotoxicity induced by cadmium in vascular endothelial cells.

METHODSAn ECV 304 cell line derived from human umbilical vein endothelial cells was adopted. Genistein/daidzein was added prior to or simultaneously with CdCl2, cell viability was determined by MTT assay, and metallothionein mRNA expression was monitored by RT-PCR method.

RESULTSCell viability was higher in isoflavone and CdCl2 co-treated groups than that in CdCl2 treated group, with CdCl2 concentration at 10, 20, 40, and 80 micromol/L, respectively. However this increase was not observed in the group treated with CdCl2 at a concentration of 60 micromol/L. Isoflavones (10(-10) mol/L to 10(-5) mol/L) were added 24 h before cells were challenged with 80 micromol/L CdCl2 for 24 h or simultaneously with 80 micromol/L CdCl2. Genistein increased cell viability only at 10(-5) mol/L, while daidzein caused a dose-dependent increase from 10(-10) mol/L to 10(-5) mol/L in co-treatment with CdCl2. In pre-treatment, genistein (10(-7) to 10(-5) mol/L) increased cell viability whereas only 10(-5) mol/L of daidzein exerted protection. Apparent protection could be found when the cells were pre-treated with 10(-5) mol/L isoflavones for over 12 h, whereas 24 h incubation was required in such a co-treatment, with the exception of daidzein that had a significant protection in only 3 h. Isoflavones (10(-6) mol/L) incubated for 3 h to 24 h, increased MT IIA and MT IF mRNA expression, but the induction could not last for more than 24 h. Co-treatment with isoflavones could induce an additional induction of MT IIA mRNA expression in cells exposed to cadmium. However, the additional induction of MT IIA and MT IF mRNA was not seen when pre-treatment was carried out with isoflavones, with the exception of an increase in MT IIA mRNA expression in the daidzein pre-treated group.

CONCLUSIONGenistein/daidzein could reverse the cytotoxicity of cadmium either in pre-treatment or in co-treatment. The protection is the strongest in 10(-5) mol/L of isoflavones with a dose-dependent pattern. There are differences between genistein and daidzein in their protective effects. Whether the protection of isoflavones is related to their capacity of inducing MT mRNA expression remains to be elucidated.

Cadmium ; toxicity ; Cell Line ; Cell Survival ; drug effects ; Endothelial Cells ; drug effects ; metabolism ; Genistein ; pharmacology ; Humans ; Isoflavones ; pharmacology ; Metallothionein ; genetics ; metabolism ; Protective Agents ; pharmacology ; RNA, Messenger ; metabolism

OBJECTIVETo investigate the possible effects of oral cadmium(Cd) exposure on the expression levels of metallothionein-I and metallothionein-II (MT-I and MT-II) mRNA and the distribution of zinc (Zn) and Cd in rat prostate.

METHODSCadmium was given to rats at doses of 50, 100, and 200 mg/kg in drinking water. The contents of Zn and Cd in prostate were measured by atomic absorption spectrometry(AAS), and the levels of MTs mRNA were determined by RT-PCR.

RESULTSAfter Cd administration, the content of Zn was decreased in both the ventral and the dorsolateral lobes of rat prostate. In 200 mg/kg Cd group, the contents of Zn in ventral prostate were 9.5 and 8.5 micrograms/g wet weight respectively after one month and six months, which were significantly lower than those of control(17.0 and 18.9 micrograms/g wet weight). In contrast, the contents of Cd in both ventral and dorsolateral lobes of prostate significantly increased with the increasing dose and time of Cd administration. It was also noted that Cd administration resulted in a significant down-regulation of the expression of MT-I and MT-II mRNA in rat ventral prostate. In 200 mg/kg Cd group after one and six months, the relative expression levels of MT-I (0.410, 0.339 respectively) and MT-II (0.100, 0.112 respectively) were significantly lower than those of MT-I (0.760, 0.830 respectively) and MT-II (0.429, 0.439 respectively) in control group.

CONCLUSIONOral Cd exposure could influence the distribution of Zn and the expression levels of MTs mRNA in rat prostate.

Administration, Oral ; Animals ; Cadmium ; metabolism ; toxicity ; Dose-Response Relationship, Drug ; Male ; Metallothionein ; genetics ; Prostate ; drug effects ; metabolism ; RNA, Messenger ; analysis ; Rats ; Zinc ; metabolism

OBJECTIVEIn order to explore the toxic effects of cadmium on functions of endocrine and exocrine of pancreas.

METHODS96 SD rats were administered with cadmium at different doses (0, 50, 100, 200 mg/L) by drinking water for 30 days, 60 days and 90 days. The contents of cadmium and zinc in the blood and pancreas, also the glucose level in blood and urine, the levels of insulin and the activity of amylase were determined. The gene expression of metallothionein (MT), insulin and pancreatic amylase were also measured.

RESULTSThe results showed that the contents of cadmium in the serum and pancreas were higher than that of the control groups (P < 0.05). The contents of zinc in serum were decreased in the groups of 100 and 200 mg/L cadmium at the 90-day. As well as increased zinc in pancreas. The gene expression of insulin was not different compared with those of the control group except the middle-dose group at the 60-day. And the expression of amylase were higher in the groups of 100 and 200 mg/L cadmium at the 60-day and the 90-day. The expression of MT-1 and -2 were higher in the pancreas after cadmium administration.

CONCLUSIONIt is suggested that cadmium could be accumulated in the pancreas and caused the change of the zinc levels. Then it resulted in the change of the expression of gene and protein, and influence of the functions of both endocrine and exocrine in pancreas.

Amylases ; metabolism ; Animals ; Cadmium ; toxicity ; Female ; Insulin ; metabolism ; Male ; Metallothionein ; metabolism ; Pancreas ; drug effects ; metabolism ; Rats ; Rats, Sprague-Dawley ; Zinc ; blood

Badu Shengji San(BDSJS) is a traditional Chinese medicine (TCM) used for drawing out toxin, eliminating suppuration and promoting granulation. Toxic minerals such as arsenic and lead are the two most important components of BDSJS. Previous hypothesis indicated that according to the compatibility theory of TCM, the toxicity of the entire BDSJS was weaker than that of arsenic and lead, respectively. In the present study, SD rats with injured skin were treated with distilled water and different composition of BDSJS (complete formulations, compatible herbs, mineral medicine containing arsenic and lead, mineral medicine containing arsenic and mineral medicine containing lead) once a day for consecutive 2 weeks. Kidney coefficient and urinary beta-N-acetyl glucosidase (NAG) were used as the indicators of renal toxicity and the content of malondiadehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), glutathione (GSH) and metallothionein (MT) in the renal tissue were measured. Our data showed that kidney coefficient, the severity of renal pathological lesion and MT level in the kidney of the entire BDSJS group decreased significantly compared with arsenic and lead group. Additionally, the NAG content of the entire BDSJS group had the decreased trend. The kidney CuZn-SOD level of the entire BDSJS group had the increased trend, but the MDA, GSH-PX, GSH level had no obvious difference. Our results suggested that compatible herbs in BDSJS relieved renal injury induced by arsenic and lead, and the attenuation mechanism may be related to MT and CuZn-SOD, but not to MDA, GSH-PX and GSH directly.
Animals ; Arsenic ; toxicity ; Body Weight ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; toxicity ; Glutathione ; metabolism ; Glutathione Peroxidase ; metabolism ; Kidney ; drug effects ; metabolism ; pathology ; Lead ; toxicity ; Male ; Malondialdehyde ; metabolism ; Metallothionein ; metabolism ; Rats ; Rats, Sprague-Dawley ; Skin ; drug effects ; Superoxide Dismutase ; metabolism

Metallothionein (MT) is a kind of metal binding protein. As an important member in metallothionein family, MT-I/II regulates metabolism and detoxication of brain metal ion and scavenges free radicals. It is capable of anti-inflammatory response and anti-oxidative stress so as to protect the brain tissue. During the repair process of brain injury, the latest study showed that MT-I/II could stimulate brain anti-inflammatory factors, growth factors, neurotrophic factors and the expression of the receptor, and promote the extension of axon of neuron, which makes contribution to the regeneration of neuron and has important effect on the recovery of brain injury. Based on the findings, this article reviews the structure, expression, distribution, adjustion, function, mechanism in the repair of brain injury of MT-I/II and its application prospect in forensic medicine. It could provide a new approach for the design and manufacture of brain injury drugs as well as for age estimation of the brain injury.
Animals ; Astrocytes/metabolism* ; Brain/metabolism* ; Brain Injuries/pathology* ; Cytokines/metabolism* ; Forensic Medicine/methods* ; Gene Expression Regulation/drug effects* ; Humans ; Metallothionein/physiology* ; Neurons/metabolism* ; Neuroprotective Agents/pharmacology* ; Oxidative Stress/drug effects*

OBJECTIVETo study the gene expression of metallothionein 1 (MT-1) isoforms in human peripheral blood lymphocytes (HPBLs).

METHODSThe expression of mRNA representing the seven active MT-1 genes was determined in HPBLs by quantitative RT-PCR before and after exposure to cadmium.

RESULTSBasal expressions of MT-1X, and MT-1A in HPBLs were similar to expression of housekeeping gene. In contrast, the basal gene expressions of MT-1H, 1F, 1E, and 1G were a little transcripts in human HPBLs. No signal was detected for MT-1B. There was a sex difference (P < 0.05). in basal gene expression of MT-1E. The levels of gene expression of MT-1A, 1E, 1F, 1G, 1H, and 1X increased, but the level of MT-1B did not increase after exposure to cadmium.

CONCLUSIONSGene expressions of MT-1G, MT-1H, MT-1F, and MT-1X in HPBLs can be used as a potential biomarker of cadmium exposure.

Adult ; Biomarkers ; metabolism ; Cadmium ; pharmacology ; Cells, Cultured ; DNA Primers ; Female ; Gene Expression Regulation ; drug effects ; Humans ; Lymphocytes ; metabolism ; Male ; Metallothionein ; genetics ; metabolism ; Protein Isoforms ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction