To investigate the effect of dehydroepiandrosterone (DHEA) on intracellular mRNA levels of peroxisome proliferator-activated receptors (PPARs) and PPAR-gamma coactivators (PGCs), we conducted a quantitative real-time RT-PCR study using HepG2 cells. Treatment with 100 micromol/l DHEA for 2-20 h caused a time-dependent elevation of mRNA levels in the cells. Upon 20 h, PPAR-alpha, -gamma1, and -gamma2 mRNAs and PGC-1alpha and -1beta mRNAs increased to 157, 161, 155, 656, and 475% of control levels, respectively (p < 0.05 each). Treatment with actinomycin D for 2.5-8 h revealed a significant stabilization effect of DHEA on PPAR-gamma1 and PGC-1alpha mRNAs at both 2.5 and 8 h incubation periods and a mild but significant stabilization effect on PGC-1beta mRNA at the 8 h incubation period suggesting that DHEA can modulate turnover of these mRNA transcripts. Basal mRNA levels of PPAR-alpha and PGC-1alpha were significantly suppressed upon 20 h treatment with cycloheximide, while those of PPAR-gamma1, -gamma2, and PGC-1beta were elevated. Cycloheximide also significantly reduced DHEA-induced accumulation of PPAR-alpha, -gamma1, -gamma2, and PGC-1alpha mRNAs, demonstrating the dependence of the DHEA action on de novo protein synthesis. The findings demonstrate that a supraphysiological concentration of DHEA can substantially influence gene expression of the PPAR signalling machinery at both transcriptional and posttranscriptional levels.

• MeSH
• cykloheximid farmakologie   MeSH
• daktinomycin farmakologie   MeSH
• dehydroepiandrosteron farmakologie   MeSH
• financování organizované MeSH
• hepatocelulární karcinom genetika   MeSH
• lidé MeSH
• messenger RNA genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• protein - isoformy genetika   MeSH
• receptory aktivované proliferátory peroxizomů genetika   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• Check Tag
• lidé MeSH

In vitro subcellular and cellular systems have important and irreplaceable roles in the metabolic investigations that precede the development of new potential drugs. Of these model systems, tissue slices are probably the nearest to in vivo conditions. From the experimental and complexity points of view, perfused organs lie midway between tissue slices and whole organism. Preparation and working with liver slices is quick and easy, and, excess material can be cryopreserved and stored untill the next experiment. Slices can be prepared from a wide variety of organs and it is possible to co-incubate them. Another important feature is the possibility of interspecies comparison of slices. Different experiments can be run both in the short-term as well as long-term incubations. Each in vitro system has an important place for example, in the development of new medicaments. It is therefore important to compare and supplement experimental results from different in vitro systems when extrapolating to in vivo situations is done.

• MeSH
• buněčné kultury * MeSH
• buňky * MeSH
• farmaceutická technologie MeSH
• farmaceutický průmysl * MeSH
• kultivační techniky * MeSH
• léčivé přípravky metabolismus   MeSH
• lidé MeSH
• suspenze * MeSH
• techniky in vitro MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH