%0 Journal Article
%T Effect of 2,4-Thiazolidinedione on Limousin Cattle Growth and on Muscle and Adipose Tissue Metabolism
%A M. Ar¨¦valo-Turrubiarte
%A L. Gonz¨¢lez-D¨¢valos
%A A. Yabuta
%A J. D. Garza
%A J. L. D¨¢valos
%A O. Mora
%A A. Shimada
%J PPAR Research
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/891841
%X The main adipogenic transcription factor PPAR possesses high affinity to 2,4-TZD, a member of the Thiazolidinedione family of insulin-sensitizing compounds used as adipogenic agents. We evaluated 2,4-TZD¡¯s effect on bovine growth and PPAR tissue expression. Seventeen Limousin bulls (18 month-old; 350£¿kg body weight (BW)) were assigned into 2 treatments: control and 2,4-TZD (8£¿mg/70£¿kg BW) and were fed until bulls reached 500£¿kg BW. They were weighed and their blood was sampled. DNA, RNA, and protein were determined in liver; skeletal muscle; subcutaneous (SC), omental, perirenal adipose tissues (AT) to determine protein synthesis rate and cellular size. Expression of PPAR mRNA was measured in liver and muscle (PPAR , - , and - ) and SC adipose tissue ( ) by real-time PCR. No significant differences were found ( ) in weight gain, days on feed, and carcass quality. Muscle synthesis was greater in controls ( ); cell size was larger with 2,4-TZD ( ). PPAR , - , and - expressions with 2,4-TZD in liver were lower ( ) than in muscle. No differences were found for PPAR¦Ã mRNA expression in SCAT. The results suggest the potential use of 2,4-TZD in beef cattle diets, because it improves AT differentiation, liver, and muscle fatty acid oxidation that, therefore, might improve energy efficiency. 1. Introduction Peroxisome proliferator-activated receptors (PPAR) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily. Three isotypes have been identified in lower vertebrates and mammals: PPAR¦Á or NR1C1; PPAR¦Â/¦Ä or NR1C2, also called NUC-1 or FAAR; PPAR¦Ã or NR1C3. These receptors exhibit different tissue distribution and functions and, to some extent, different ligand specificities. Mechanistically, they form heterodimers with the retinoid X receptor (RXR) and activate transcription by binding to a specific DNA element, termed the peroxisome proliferator response element (PPRE), in the regulatory region of a variety of genes encoding proteins that are involved in lipid metabolism [1] and energy balance [2¨C4]. The Thiazolidinediones (TZDs) are PPAR¦Ã agonists that possess clinical antidiabetic efficacy, mainly through their actions in adipose tissues [3]. The influence of TZD on adipose differentiation has been demonstrated through modifications on adipose tissue deposition and increases of intramuscular (IM) fat in meat animals [5, 6]; on the other hand, Michalik et al. [3] mentioned that some TZD may act on different PPAR, especially PPAR¦Á. Marbling or IM fat has been positively correlated with meat quality [7] because of the
%U http://www.hindawi.com/journals/ppar/2012/891841/