Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Contrast-enhanced magnetic resonance imaging (CE-MRI) is a valuable technique for the diagnosis of liver diseases. As gadocoletic acid trisodium salt (B22956/1), a new contrast agent showing high biliary excretion, may be potentially advantageous in hepatobiliary imaging, the aim of the study was to investigate the molecular mechanisms of hepatic transport of the B22956 ion in a cellular model of hepatic tumor. B22956 ion uptake was measured in tumoral (HepG2) and nontumoral (Chang liver) hepatic cell lines. Absolute quantitative real-time reverse transcriptase (RT)-polymerase chain reaction (PCR) analyses, using cloned PCR products as standards, were performed on total RNA of both cell lines and normal liver to evaluate the transcription of 12 transport genes: SLCO1A2, SLCO2B1, SLCO1B1, SLCO3A1, SLCO4A1, SLCO1B3, SLC22A7, SLC22A8, SLC22A1, SLC10A1, SLC15A1, and SLC15A2. B22956 transport was more efficient in Chang liver than in HepG2 cells and was inhibited by cholecystokinin-8, a specific substrate of OATP1B3. Real-time RT-PCR analyses revealed different transcription profiles in the tumoral and nontumoral cell lines. Compared with normal liver, the expression of SLCO1B1, SLCO3A1, and SLCO1B3 was greatly repressed in HepG2 cells, whereas SLCO2B1, SLC22A7, and SLC22A8 expression was either maintained or increased. On the contrary, in Chang liver cells, SLC22A7 and SLC22A8 genes were undetectable, whereas the expression of SLCO3A1, SLCO4A1, and SLCO1B3 was similar to normal liver. Transport studies and gene expression analyses indicated that B22956 ion is a good substrate to the liver-specific OATP1B3, reported to be poorly expressed or absent in human liver tumors. Therefore, B22956 may be helpful in detecting hepatic neoplastic lesions by CE-MRI.
 ...
PMID:Molecular determinants in the transport of a bile acid-derived diagnostic agent in tumoral and nontumoral cell lines of human liver. 1689 78

The changes in endometrial homeostasis found in women with polycystic ovarian syndrome (PCOS) could be associated with alterations in the intracrine metabolism of steroid hormones. The uptake of dehydroepiandrosterone-sulphate (DHEA-S), precursor of the intracrine pathway, is achieved by transporters, such as organic anion transporter polypeptides (OATPs), and molecules with oestrogenic activity, such as androst-5-ene-3beta,17beta-diol (androstenediol), can be generated. We aimed to determine androstenediol generation and the expression of OATPs in human endometria throughout the menstrual cycle and in endometria from PCOS women. Endometrial samples were obtained from control women in the proliferative phase (control endometria (CEp), n=7), secretory phase (CEs, n=7), and from PCOS patients (PCOSEp, n=7). The mRNA levels of OATP-B, OATP-D and OATP-E were measured by reverse transcriptase polymerase chain reaction (RT-PCR) and protein levels of OATP-E by immunofluorescence; 3beta-hydroxysteroid dehydrogenase (HSD) by immunohistochemistry/Western blot; the metabolism of DHEA to androstenediol was evaluated by thin layer chromatography-high-performance liquid chromatography (TLC-HPLC). Lower levels of OATP-E transcript were obtained in PCOSEp (p<0.05) compared with CEp, while OATP-E protein levels (p<0.05) and DHEA conversion to androstenediol (p<0.01) were higher in PCOSEp. Lower 3beta-(hydroxysteroid dehydrogenase) HSD protein levels were found in PCOSEp (p<0.05) (Western blot, immunohistochemistry). These results reveal a higher capacity of the endometria from PCOS women to metabolise DHEA to androstenediol, which, coupled with the high oestrogen sensitivity previously found in these endometria, may account for the increase in cell proliferation in PCOSEp already reported.
 ...
PMID:The conversion of dehydroepiandrosterone into androst-5-ene-3beta,17beta-diol (androstenediol) is increased in endometria from untreated women with polycystic ovarian syndrome. 2062 Jan 58