Carcass grade primarily depends on marbling of intramuscular fat, which is associated with the texture and tenderness of beef. Accordingly, various economical molecular tests for high intramuscular fat in beef have been attempted. Especially, Hanwoo (Korean Cattle) intramuscular fat has higher levels of monounsaturated fatty acids than that in the beef of other cattle. Intramuscular fats are associated with levels of lipid metabolic genes in the liver transcriptome. Therefore, hepatic triglyceride synthesis can considerably increase intramuscular fat. To investigate the relationship between hepatic lipogenesis and carcass grade, we analyzed 52 Hanwoo liver samples from domestic farms, and evaluated lipid levels and transcript levels of glucose and lipid metabolism-related genes according to carcass grade. Oil-Red-O staining revealed fatty livers in high carcass grades. Moreover, we found significantly higher levels of mRNA for lipogenesis, glycolysis, and triglyceride synthesis genes in high carcass grade livers. Importantly, progesterone receptor membrane component 1 (Pgrmc1) levels were significantly lower in high carcass grade livers. As Pgrmc1 suppression is correlated with induction of de novo lipogenesis (DNL) and glycolysis genes, it has a diagnostic impact for high carcass grades. These results could be used for genetic improvements in carcass grades of cattle. More importantly, as Pgrmc1 can be detected in blood peripheral nucleated cells, it also has value for rapid blood diagnosis.

Introduction
Materials and Methods
    Animals
    RNA isolation, reverse transcription, and qRT-PCR
    Oil Red O staining
    Cell culture
    siRNA transfection
    Statistical analysis
Results
    High potential for fatty liver occurrence exists inhigh grade carcasses
    Gene levels related to de novo lipogenesis areupregulated in high grade carcasses
    Gene levels related to glycolysis are upregulatedin high grade carcasses
    Low levels of Pgrmc1 mRNA were observed inlivers from high grade carcasses
    PGRMC1 down-regulation was correlated with glycolysisinduction
Discussion
References

• Sang Ryeol Lee(College of Veterinary Medicine, Chungnam National University)
• Chang Yeon Kim(College of Veterinary Medicine, Chungnam National University)
• Young Ho Lee(College of Veterinary Medicine, Chungnam National University)
• Jong-ho Kim(Animal Health Division, Institute of Health & Environment in Daejeon)
• Si-yun Ryu(College of Veterinary Medicine, Chungnam National University)
• Bae-keun Park(College of Veterinary Medicine, Chungnam National University)
• Eui-Ju Hong(College of Veterinary Medicine, Chungnam National University) Corresponding author