Exercise training decreases hepatic SCD-1 gene expression and protein content in rats.
Stearoyl-CoA desaturase-1 (SCD-1) is the rate limiting enzyme in the biosynthesis of saturated-derived monounsaturated fats that are the major constituents of very-low-density-lipoproteins-triacylglycerol (VLDL-TAG) and are involved in regulating cellular metabolism. The purpose of this study was to evaluate the effects of an 8-week exercise training program on the hepatic gene expression of this crucial enzyme. Female rats either trained (TR) or kept sedentary (Sed) for 8 weeks were submitted either to standard (SD) diet for 8 or for 6 weeks followed by high-fat (HF; 42% kcal) diet for 2 weeks. The 2-week-high fat feeding resulted in an increase in liver triacylgycerol (TAG), plasma free-fatty-acids (FFA), abdominal fat mass, sterol-regulatory-element-binding protein-1c (SREBP-1c), and carbohydrate-response-element-binding protein (ChREBP) gene expression in liver along with a decrease in SCD-1 gene expression and plasma and liver SCD-1 desaturation index (C16:1/C16:0). Liver TAG, plasma FFA, SREBP-1c mRNA, and SCD-1 desaturation indexes (C16:1/C16:0; C18:1/C18:0) were not changed in liver or in plasma by the training program. Nevertheless, training resulted in an important decrease in fat mass (P < 0.01), hepatic SCD-1 mRNA levels (P < 0.01), and protein content (P < 0.05) in both SD and HF fed rats. It is concluded that despite an absence of decreased liver TAG, exercise training contributes to the proper regulation of fat metabolism by down-regulating hepatic SCD-1 gene expression and protein content.
Yasari
Siham
S
Department of Kinesiology, University of Montreal, Montreal, Canada. syasari@uottawa.ca
Prud'homme
Denis
D
Wang
Donghao
D
Jankowski
Marek
M
Levy
Emile
E
Gutkowska
Jolanta
J
Lavoie
Jean-Marc
JM
D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism; D004041:Dietary Fats / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D050356:Lipid Metabolism; D008099:Liver / Q000201:enzymology* / Q000378:metabolism; D010805:Physical Conditioning, Animal; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013230:Stearoyl-CoA Desaturase / Q000235:genetics* / Q000378:metabolism; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; C442825:Mlxipl protein, rat; D012333:RNA, Messenger; D051780:Sterol Regulatory Element Binding Protein 1; D014280:Triglycerides; D013230:Stearoyl-CoA Desaturase