Patterns of albumin and general protein synthesis in rat liver as revealed by gel electrophoresis (original) (raw)
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Regulation of albumin synthesis in rat liver
Molecular Biology Reports, 1979
The present report reviews our findings on the subcellular distribution of albumin mRNA in rat fiver under normal and abnormal physiologic conditions, the identification of albumin mRNA in specific mRNP complexes in liver cytosol of starved rats, and evidence for albumin mRNA sequences in a higher molecular weight nuclear precursor to cytoplasmic albumin mRNA.
Hepatology, 1997
to examine protein metabolism in man, especially for whole Although the metabolism of liver-derived plasma probody measurements. Whole body protein synthesis has been teins such as albumin has been extensively studied, hushown to change after surgery of moderate severity, 5,6 and to man hepatic protein synthesis as a whole has not been increase after major trauma. On the other hand, in major well characterized, because a reproducible model for obtrauma, whole body protein degradation increases even more taining human liver tissue has not been available. In this than protein synthesis. 7 However, it is preferrable that indistudy, the fractional synthesis rates of total liver protein vidual tissues are studied separately, because studies of the and albumin in vivo were determined simultaneously in whole body do not differentiate responses at the organ level. nine subjects undergoing elective laparoscopic cholecys-Thus, stable isotope techniques have also been used to assess tectomy. L-[ 2 H 5 ]phenylalanine (45 mg/kg body wt) was protein synthesis in human skeletal muscle. 8 Essén et al.
Kinetic nephelometric determination of albumin produced by rat hepatocytes in culture
Clinica Chimica Acta, 1996
A kinetic immunonephelometric method for the determination of albumin produced by rat hepatocytes in culture is described. This assay is simple, rapid and sensitive. The methodology allows detection of 0.7 mg/l albumin in 200/tl of culture medium. Within-run precision CVs for three levels of concentrations were under 1.0% and between-day precision CVs were under 4.1%. The range of measurement obtained using appropriately diluted samples was 1.2 to 74 mg/l. The rabbit lgG fraction to rat albumin used in this method did not cross-react with albumin from cow, allowing the use of fetal calf serum in the medium. The method described can thus be used easily for the assessment of albumin synthesis in cellular studies using isolated hepatocytes
Regulation of albumin mRNA in H4 rat hepatoma cells by the availability of essential amino acids
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1988
Deprivation of cultured 1t4 rat hepatoma cells for an essential amino acid (icucin~ methionine, tryptophan or phenylalanine) under conditions in wh~eh the cells remain highly viable leads to a decrease in cytoplasmic albumin mRNA. The magnitude of this decrease is greatest in tryptophan-d~.prived and phenyl~nni~.prived cells. In the tryptoplum-deprived cells there is approximately a 15-17-fold decrease in albumin mP,,NA relative to total cytoplasmic RNA, and a 7-8-fold specific decrease in albumin mRNA relative to a-tubulin mRNA. Deprivation d the 1-14 celts for icucine or tryptophan causes appmxinmtely a 40--4S% decrease in albmnin gene transcription; however, this effect does not account for the 15-17-fold decrease in albumin mRNA abundancy caused by tryI~tophan limitation, or the greater effect of tryptophan limitation as compared to leucine limitation on albumin mRNA. Therefore, the decrease in albumin mRNA caused by tryptophan limitation is caused pr~,narily by a post-transeriptional reg,~latory mechanism.
Proceedings of the National Academy of Sciences, 1985
A 23-kilobase-pair segment of DNA containing the entire mouse serum albumin gene as well as 2.2 kilobase pairs of 5' and 4.3 kilobase pairs of 3' flanking sequences has been introduced into pSV2dhfr, a plasmid in which expression of the mouse dihydrofolate reductase cDNA is under the control of simian virus 40 sequences. This vector, pSV2dhfr-alb, was used to transfect differentiated and variant dedifferentiated rat hepatoma cells. Nine independent clones of transfected differentiated cells secrete considerable amounts of mouse albumin, while the expression of the normal rat albumin is the same as in nontransfected cells. In contrast, only small amounts of mouse and rat albumin are produced by transfected dedifferentiated cells. The amounts of albumin mRNA present in the cells are consistent with the amounts of albumin produced. These results show that a transfected gene can be regulated in a fashion consistent with the overall differentiation profile of the cell.