Expression of peroxisome proliferator-activated receptor (PPARγ) mRNA in adipose and muscle tissue of Holstein and Charolais cattle

Abstract

Peroxisome proliferator-activated receptor γ(PPARγ) regulates adipogenesis and lipid metabolism-related gene transcripts. The role, however, of PPARγ in different adipose depots and muscle in Holstein and Charolais cattle is still unclear. We used 20 animals (10 from each breed) for semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) to measure PPARγ mRNA levels in subcutaneous (SC), perirenal (PR), omental (OM), and intramuscular (IM) adipose depots as well as longissimus muscle (MU). IM fat was dissected from muscle tissue in MU. Holstein were characterized by their higher OM (P < 0.01) and PR (P < 0.05) fat weights while the Charolais had a higher body weight (P < 0.001) and a larger longissimus muscle area (P < 0.001). The IM fat content and marbling scores tended to be higher in Holstein. No significant differences in PPARγ mRNA expression were observed between these two breeds for any tissue. In both breeds, MU PPARγ had the lowest expressed mRNA level (P < 0.05). In the IM fat depot, expression was higher (P < 0.05) than MU, but lower than the SC, PR, and OM fat depot PPARγ mRNA levels. Only OM PPARγ mRNA levels were higher (P < 0.05) than SC and PR in Charolais. To characterise the role of PPARγ mRNA in bovine adipogenesis, correlations were performed among PPARγ mRNA, carcass characteristics, and adipogenesis-related genes. Key words: Adipose tissue, muscle tissue, PPARγ, cattle