Different effects of pioglitazone and rosiglitazone on lipid metabolism in mouse cultured liver explants.
BACKGROUND
Pioglitazone (PIO) and rosiglitazone (ROSI) are widely used as oral antidiabetic agents for treatment of type 2 diabetes. Although these medications exert similar effects on blood glucose, recent clinical studies indicated that PIO has a more pronounced beneficial effect on lipid parameters than ROSI. In order to get further insight into the lipid effects of both drugs, we tested whether PIO, compared to ROSI, could exert direct effects on lipid liver metabolism in relation with plasma lipids.


METHODS
We performed in vitro studies using mice liver slices incubated 21 h either with ROSI (1 micromol/L) or PIO (7.5 micromol/L).


RESULTS
We showed that both glitazones slightly reduced HMG-CoA reductase mRNA levels at the same degree but only PIO reduced intracellular cholesterol content, suggesting an alteration of cholesterol uptake rather than an inhibition of cholesterol biosynthesis. This concept was supported by the reduction of scavenger receptor class B type I expression, hepatic lipase activity and high-density lipoprotein cholesterol uptake in PIO-treated liver explants. Conversely, hepatic lipase mRNA levels were increased 3.5-fold. ROSI, but not PIO, induced acetyl-CoA carboxylase and fatty acid synthase gene expression and increased apoB secretion suggesting a stimulation of lipogenesis. Concurrently, peroxisome proliferator-activated receptor-gamma mRNA levels were induced by ROSI and not significantly changed by PIO. Besides, PIO appeared to be a more potent activator of AMP-Activated Protein Kinase than ROSI.


CONCLUSIONS
PIO and ROSI exert specific direct effects on liver and extrapolating these data to humans could explain the significant improvements in plasma lipids observed in diabetic patients treated with PIO.
Djaouti
Louiza
L
UMR 866 INSERM-UB, Team Physiopathology of dyslipidemias, Faculty of Sciences Gabriel, University of Burgundy, Dijon 21000, France.
Jourdan
Tony
T
Demizieux
Laurent
L
Chevrot
Michaël
M
Gresti
Joseph
J
Vergès
Bruno
B
Degrace
Pascal
P
D000818:Animals; D008076:Cholesterol, HDL / Q000378:metabolism; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008049:Lipase / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D047495:PPAR gamma / Q000378:metabolism; D000077205:Pioglitazone; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology*; D046509:Tissue Culture Techniques
D008076:Cholesterol, HDL; D006442:Glycated Hemoglobin; D008049:Lipase; D047495:PPAR gamma; D000077205:Pioglitazone; D000077154:Rosiglitazone; D045162:Thiazolidinediones; C495700:Lipc protein, mouse