Recently, an increase in gammaglutamyltranspeptidase (GGT) activity and mRNA in liver of hypothyroid rats has been reported. The aim of this study was to verify if triiodothyronine (T3) can directly affect GGT expression in primary cultures of rat hepatocytes. Results obtained from adult rat hepatocytes cultured in serum-free medium demonstrate: 1) a rise in GGT mRNA level magnified by dexamethasone during the maintenance of hepatocytes in culture which parallels the stimulation of GGT activity; 2) a negative effect of T3 on GGT activity of cultured hepatocytes which reflects a specific inhibition of GGT gene expression. The T3 effect on GGT expression in cultured hepatocytes is in line with previous observations on hypothyroid rat liver suggesting an important role for thyroid hormone in maintaining the differentiated adult liver phenotype in the rat.

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-2007-979944DOI Listing

Publication Analysis

Top Keywords

rat hepatocytes
12
ggt activity
12
expression cultured
8
ggt expression
8
cultured hepatocytes
8
ggt
7
hepatocytes
6
rat
5
triiodothyronine decreases
4
decreases gammaglutamyltranspeptidase
4

Similar Publications

Traditional Japanese medicines, i.e., Kampo medicines, consist of crude drugs (mostly plants) that have empirical pharmacological functions ('' in Japanese), such as clearing heat.

View Article and Find Full Text PDF

Insulin Receptor Substrate-2 Regulates the Secretion of Growth Factors in Response to Amino Acid Deprivation.

Int J Mol Sci

January 2025

Department of Animal Resource Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.

Insulin receptor substrates (IRSs) are well-known mediators of the insulin and insulin-like growth factor (IGF)-I signaling pathways. We previously reported that the protein levels of IRS-2, a molecular species of IRS, were upregulated in the livers of rats fed a protein-restricted diet. This study aimed to elucidate the physiological role of IRS-2, whose level increases in response to protein restriction in cultured hepatocyte models.

View Article and Find Full Text PDF

We previously isolated a cDNA clone for galactosylceramide expression factor 1, which is the rat homologue of hepatocyte-growth-factor-regulated tyrosine kinase substrate (HGS) and induces galactosylceramide expression and morphological changes in COS-7 cells, and reported that overexpression of HGS induced morphological changes in canine kidney epithelial MDCK cells. HGS is a component of the endosomal sorting complexes required for transport machinery that mediates endosomal multivesicle body formation. In this study, the overexpression of HGS induced epithelial-mesenchymal transition and caused transformation in MDCK cells, whereas the overexpression of a coiled-coil domain of HGS inhibited induction of epithelial-mesenchymal transition by HGF stimulation.

View Article and Find Full Text PDF

The transgenic MutaMouse hepatocyte mutation assay in vitro: Mutagenicity and mutation spectra of six substances with different mutagenic mechanisms.

Mutat Res Genet Toxicol Environ Mutagen

January 2025

Free University of Berlin, Institute of Pharmacy, Pharmacology and Toxicology, Berlin, Germany; BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany.

Mutagenicity testing is a component of the hazard assessment of industrial chemicals, biocides, and pesticides. Mutations induced by test substances can be detected by in vitro and in vivo methods that have been adopted as OECD Test Guidelines. One of these in vivo methods is the Transgenic Rodent Assay (TGRA), OECD test guideline no.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!