Skip to main page content home current issue archive feedback subscriptions alerts help keywords go advanced â» user name password sign in expression of cytochromes p450, conjugating enzymes and nuclear receptors in human hepatoma heparg cells caroline aninat 1, amã©lie piton 1, denise glaise , typhen le charpentier , sophie langouã«t , fabrice morel , christiane guguen-guillouzo and andrã© guillouzo institut national de la santã© et de la recherche mã©dicale (inserm) u620, universitã© de rennes 1, ifr140, rennes, france (c. generic viagra without prescriptions A. female viagra for sale , a. P. viagra sale , s. buy viagra online australia fast delivery L. canadian generic viagra online , f. M. buy viagra online in usa , a. buy viagra in norway G. is viagra a prescription drug ); and inserm u522, hã´pital pontchaillou, ifr 140, rennes, france (d. G. viagra forums uk , t. L. ordering viagra online safe C. where can i buy viagra in perth , c. viagra sales statistics 2010 G-g. lowest price for generic viagra ) address correspondence to: andrã© guillouzo, inserm u620, detoxication et rã©paration tissulaire, facultã© des sciences pharmaceutiques et biologiques, universitã© de rennes i, 35043 rennes cedex, france. cheapest prices on viagra E-mail: andre. cheapest viagra pills Guillouzo{at}univ-rennes1. Viagra jetlag Fr abstract most human hepatocyte cell lines lack a substantial set of liver-specific functions, especially major cytochrome p450 (p450)-related enzyme activities, making them unrepresentative of in vivo hepatocytes. We have used the heparg cells, derived from a human hepatocellular carcinoma, which exhibit a high differentiation pattern after 2 weeks at confluency to determine whether they could mimic human hepatocytes for drug metabolism and toxicity studies. get private prescription viagra We show that when passaged at low density, these cells reversed to an undifferentiated morphology, actively divided, and, after having reached confluency, formed typical hepatocyte-like colonies surrounded by biliary epithelial-like cells. Does viagra really work By contrast, when seeded at high density, hepatocyte-like clusters retained their typical differentiated morphology. generic viagra without prescriptions Transcripts of various nuclear receptors (aryl hydrocarbon receptor, pregnane x receptor, constitutive androstane receptor, peroxisome proliferator-activated receptor î±), p450s (cyp1a2, 2c9, 2d6, 2e1, 3a4), phase 2 enzymes (ugt1a1, gsta1, gsta4, gstm1), and other liver-specific functions were estimated by reverse transcriptase-quantitative polymerase chain reaction and were found to be expressed, for most of them, at comparable levels in both confluent differentiated and high-density differentiated heparg cells and in cultured primary human hepatocytes. For several transcripts, the levels were strongly increased in the presence of 2% dimethyl sulfoxide. generic viagra without prescriptions Measurement of basal activities of several p450s and their response to prototypical inducers as well as analysis of metabolic profiles and cytotoxicity of several compounds confirmed the functional resemblanc. Does walmart sell viagra