Expression of porcine transcription factors and genes related to fatty acid metabolism in different tissues and genetic populations

Several transcription factors are involved in regulating lipid metabolism i n various tissues of animals. Adipocyte determination and differentiation-d ependent factor 1 (ADD1), peroxisome proliferator activated receptor alpha (PPAR alpha), and peroxisome proliferator activated receptor gamma (PPAR ga mma) regulate both lipogenesis and fatty acid oxidation. We determined the tissue distribution and genetic difference in mRNA concentrations of these transcription factors in two genetic populations of pigs (Newsham XL-sired Newsham Landrace x Large White Duroc and Duroc-sired US Yorkshire x Duroc-L andrace). We also determined the tissue distribution and genetic difference in the mRNA concentration of fatty acid synthase (FAS) and acyl-CoA oxidas e (ACO). Our data showed that ADD1 was highly expressed in adipose tissue a nd liver and that mRNA concentrations of ADD1 were similar between the two genotypes. The PPAR alpha mRNA concentration was high in adipose tissue and was similar between the two genotypes. In both populations, PPAR gamma mRN A was detected only in adipose tissue. There was no difference between the two genotypes in PPAR gamma mRNA concentration. The ACO mRNA was expressed in adipose tissue, skeletal muscle, and liver with no difference between ge notypes. The FAS mRNA concentration in adipose tissue was seven times highe r than that in the liver. There was no detectable FAS mRNA in skeletal musc le. These data support the concept that pig adipose tissue has considerable capability for fatty acid oxidation and synthesis. The uniqueness of expre ssion patterns for FAS and ADD1 mRNA further indicates that adipose tissue is significantly involved in fatty acid and triacylglycerol synthesis in pi gs.