Whey Protein Intake Modulates Lipid Metabolism by Transcriptionally Affecting PPARs and SREBP1c and Their Downstream Enzymes in Mice

Abstract

Background: The effects of whey protein intake on the transcriptional expression of genes related to lipid metabolism in mice were investigated herein. Methods: For 4 weeks, mice were fed AIN-93G composed of either casein or whey protein as the protein source. Then the gastrocnemius muscle, liver, and epididymal adipose tissue were excised. Expression levels of the transcription factors, PPARα, PPARγ, and SREBP1c, and those of the enzymes modulated by these factors, HSL, LPL, ACCα, and FAS, were measured by real-time PCR. The effects of whey protein were compared to those of the case in control. Results: The mRNA expression of PPARα was enhanced in the gastrocnemius muscle, while that of PPARγ was increased in the liver and epididymal adipose tissue. The expression of HSL and LPL was increased in the epididymal adipose tissue and gastrocnemius muscle, respectively. The mRNA expression of SREBP1c was suppressed in all of the three tissues. The expression of ACCα was suppressed in the gastrocnemius muscle and liver, while that of FAS was suppressed in all of the three tissues. Conclusions: These results indicate that whey protein intakes transcriptionally modulate PPARs and SREBP1c directing lipid metabolism toward the enhancement of triglyceride breakdown and suppression of fatty acid synthesis.