Article date: September 2018
By: Hyekyung Yang, Dong Ho Suh, Dae Hee Kim, Eun Sung Jung, Kwang‐Hyeon Liu, Choong Hwan Lee, Cheol‐Young Park in Volume 175, Issue 17, pages 3610-3625
Background and Purpose
Thiazolidinediones, acting as PPAR‐γ ligands, reduce hepatic steatosis in humans and animals. However, the underlying mechanism of this action remains unclear. The purpose of this study was to investigate changes in hepatic metabolites and lipids in response to treatment with the thiazolidinedione pioglitazone in an animal model of obese Type 2 diabetes.
Experimental Approach
Male Otsuka Long‐Evans Tokushima Fatty (OLETF) rats were orally administered either vehicle (control) or pioglitazone (30 mg·kg−1) and fed a high‐fat diet (60% kcal fat) for 12 weeks. Hepatic metabolites were analysed via metabolomic and lipidomic analyses. Gene expression and PLA2 activity were analysed in livers from pioglitazone‐treated and control rats.
Key Results
OLETF rats that received pioglitazone showed decreased fat accumulation and improvement of lipid profiles in the liver compared to control rats. Pioglitazone treatment significantly altered levels of hepatic metabolites, including free fatty acids, lysophosphatidylcholines and phosphatidylcholines, in the liver. In addition, pioglitazone significantly reduced the expression of genes involved in hepatic de novo lipogenesis and fatty acid uptake and transport, whereas genes related to fatty acid oxidation were up‐regulated. Gene expression and enzyme activity of PLA2, which hydrolyzes phosphatidylcholines to release lysophosphatidylcholines and free fatty acids, were significantly decreased in the livers of pioglitazone‐treated rats compared to control rats.
Conclusions and Implications
Our results present evidence for the ameliorative effect of pioglitazone on hepatic steatosis, largely due to the regulation of lipid metabolism, including fatty acids, lysophosphatidylcholines, phosphatidylcholines and related gene‐expression patterns.
DOI: 10.1111/bph.14434
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