Isolation of Metallothionein Isoforms in Rat Liver

The expression of metallothionein (MT)-1 and -2 mRNAs in rat liver following administration of Cd or Cu was investigated using specific oligonucleotides. The specificity was confirmed using a competitive prehybridization assay. Cd injection caused a biphasic induction of both isoform mRNAs, whereas Cu induced a sustained, monophasic response. Analysis of polyribosomal RNA showed that, after both Cd and Cu treatments, the recruitment of MT-1 mRNA into polyribosomes paralleled the increase in transcription, but the increase of polyribosomal MT-2 mRNA was less than that of total MT-2 mRNA. This indicates that not all the MT-2 mRNA induced was translated, suggesting that there is translational control of MT-2 mRNA expression, but not of MT-1 mRNA. This hypothesis was supported by the observation that, after Cu treatment, the induction of MT-1 protein was induced to the same extent as MT-1 mRNA, whereas the total MT protein (MT-1+MT-2) was increased far less (7-fold) than MT-2 mRNA (30-fold).

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Ontogenic changes in hepatic metallothionein isoforms in prenatal and newborn rats

Biochemistry and Cell Biology ◽

10.1139/o93-022 ◽

1993 ◽

Vol 71 (3-4) ◽

pp. 133-140 ◽

Cited By ~ 19

Author(s):

Hing Man Chan ◽

M. George Cherian

Keyword(s):

Rat Liver ◽

Fetal Liver ◽

Immunohistochemical Localization ◽

Enzyme Linked Immunosorbent Assay ◽

Apparent Difference ◽

Newborn Rats ◽

Newborn Rat ◽

Pregnant Rats ◽

Metallothionein Isoforms ◽

Species Specific

The relative quantities of the two metallothionein isoforms (MT-1 and MT-2) in prenatal and newborn rat livers have been quantified using a competitive enzyme-linked immunosorbent assay with two specific polyclonal antisera. Both MT isoforms were detected in fetal liver on gestation day 16 and their levels continued to increase into the neonatal period. A concomitant increase was observed in plasma MT levels in the pregnant rats. The level of MT-2 was higher (75%) than that of MT-1 in the liver of both prenatal and neonatal rats. Both hepatic MT isoforms showed a significant correlation (P < 0.05) with the hepatic Zn level. Immunohistochemical localization of MT isoforms showed no apparent difference in intracellular distribution. Both MT isoforms were mainly cytoplasmic in fetal rat liver. Intense intranuclear staining was observed in newborn rat liver when the total MT concentration reached a maximum of over 1 mg MT/g tissue. The nuclear MT staining decreased with age, and at day 7, approximately equal concentrations of MT were found in nucleus and cytoplasm. When the newborn rats (1 day old) were injected with Zn (10 mg/kg), both MT isoforms were induced on days 2 and 7. Injection of Cd (1 mg/kg) increased the hepatic MT levels only on day 7. The level of MT-2 remained higher than that of MT-1 in all cases. These results suggest that both MT isoforms play a similar role in the metabolism of Zn during early development and the relative abundance of the MT isoforms may be a species-specific phenomenon.Key words: ontogeny, metallothionein, isoforms, immunohistochemistry, metals.

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Initial Polymerization Sites Indicated During Mitochondrial Oxidation of Diaminobenzidine after Toluene Treatment

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079498 ◽

1977 ◽

Vol 35 ◽

pp. 408-409

Author(s):

W. A. Shannon ◽

M. A. Matlib

Keyword(s):

Membrane Permeability ◽

Cytochrome Oxidase ◽

Rat Liver ◽

Precise Definition ◽

Cytochemical Localization ◽

Oxidative Reaction ◽

Mitochondrial Oxidation ◽

Definition Of ◽

Exogenous Substrates

Numerous studies have dealt with the cytochemical localization of cytochrome oxidase via cytochrome c. More recent studies have dealt with indicating initial foci of this reaction by altering incubation pH (1) or postosmication procedure (2,3). The following study is an attempt to locate such foci by altering membrane permeability. It is thought that such alterations within the limits of maintaining morphological integrity of the membranes will ease the entry of exogenous substrates resulting in a much quicker oxidation and subsequently a more precise definition of the oxidative reaction.The diaminobenzidine (DAB) method of Seligman et al. (4) was used. Minced pieces of rat liver were incubated for 1 hr following toluene treatment (5,6). Experimental variations consisted of incubating fixed or unfixed tissues treated with toluene and unfixed tissues treated with toluene and subsequently fixed.

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Effects of 5-5'-Diphenyl-2-thiohydantoin (DPTH) and Thyroxine on the Ultrastructure and Chemical Composition of Rat Liver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066917 ◽

1971 ◽

Vol 29 ◽

pp. 570-571

Author(s):

E. A. Elfont ◽

R. B. Tobin ◽

D. G. Colton ◽

M. A. Mehlman

Keyword(s):

Chemical Composition ◽

Rat Liver ◽

Future Study ◽

Mode Of Action ◽

Liver Mitochondria ◽

Rat Liver Mitochondria ◽

Effective Inhibitor ◽

Biochemical Effects ◽

Glycerophosphate Dehydrogenase ◽

Stimulation Of

Summary5,-5'-diphenyl-2-thiohydantoin (DPTH) is an effective inhibitor of thyroxine (T4) stimulation of α-glycerophosphate dehydrogenase in rat liver mitochondria. Because this finding indicated a possible tool for future study of the mode of action of thyroxine, the ultrastructural and biochemical effects of DPTH and/or thyroxine on rat liver mere investigated.Rats were fed either standard or DPTH (0.06%) diet for 30 days before T4 (250 ug/kg/day) was injected. Injection of T4 occurred daily for 10 days prior to sacrifice. After removal of the liver and kidneys, part of the tissue was frozen at -50°C for later biocheailcal analyses, while the rest was prefixed in buffered 3.5X glutaraldehyde (390 mOs) and post-fixed in buffered 1Z OsO4 (376 mOs). Tissues were embedded in Araldlte 502 and the sections examined in a Zeiss EM 9S.Hepatocytes from hyperthyroid rats (Fig. 2) demonstrated enlarged and more numerous mitochondria than those of controls (Fig. 1). Glycogen was almost totally absent from the cytoplasm of the T4-treated rats.

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Effects of Steroids on Fetal Rat Liver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063664 ◽

1969 ◽

Vol 27 ◽

pp. 350-351

Author(s):

F. G. Zaki

Keyword(s):

Liver Injury ◽

Rat Liver ◽

Fetal Liver ◽

Dosage Level ◽

Maternal Plasma ◽

Methyl Prednisolone ◽

Fetal Rat ◽

Toxic Agents ◽

Fetal Rat Liver ◽

Neonatal Liver

Fetal and neonatal liver injury induced by agents circulating in maternal plasma, even though well recognized, its morphological manifestations are not yet established. As part of our studies of fetal and neonatal liver injury induced by maternal nutritional disorders, metabolic impairment and toxic agents, the effects of two anti-inflammatory steroids have been recently inves tigated.Triamcinolone and methyl prednisolone were injected each in a group of rats during pregnancy at a-dosage level of 2 mgm three times a week. Fetal liver was studied at 18 days of gestation. Litter size and weight markedly decreased than those of control rats. Stillbirths and resorption were of higher incidence in the triamcinolone group than in those given the prednisolone.

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Effects of Hypophysectomy on the Fine Structure of Rat Liver Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060799 ◽

1967 ◽

Vol 25 ◽

pp. 156-157

Author(s):

Robert R. Cardell

Keyword(s):

Electron Microscopy ◽

Fine Structure ◽

Rat Liver ◽

Liver Cell ◽

Anterior Pituitary ◽

Liver Cells ◽

Biochemical Studies ◽

Liver Functions ◽

Rat Liver Cells ◽

And Control

Hypophysectomy of the rat renders this animal deficient in the hormones of the anterior pituitary gland, thus causing many primary and secondary hormonal effects on basic liver functions. Biochemical studies of these alterations in the rat liver cell are quite extensive; however, relatively few morphological observations on such cells have been recorded. Because the available biochemical information was derived mostly from disrupted and fractionated liver cells, it seemed desirable to examine the problem with the techniques of electron microscopy in order to see what changes are apparent in the intact liver cell after hypophysectomy. Accordingly, liver cells from rats which had been hypophysectomized 5-120 days before sacrifice were studied. Sham-operated rats served as controls and both hypophysectomized and control rats were fasted 15 hours before sacrifice.

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