In vivo incorporation of tritium to measure lipogenesis in red skeletal muscle: significance of a nonlipogenic diet in LA/N-fa(k)("corpulent") and Zucker fa rat strains
Date of Award
College of Science
Type of Degree
E. Bowie Kahle
Leonard J. Deutsch
David S. Mallory
Skeletal muscle lipogenesis in rodents may equal that of liver but its importance in the obese animals is not known. We evaluated the rate of fatty acid and triglyceride synthesis and storage content in red skeletal muscles, liver, inguinal fat, and retroperitoneal fat of the LA/N-fak (“corpulent”) and Zucker fa obese rat strains. Obese-lean pairs of both rat strains, weaned at 32 days, fed a nonlipogenic diet (54% starch for 21 days) were either dosed with 2 µCi 3H-H2 O per gram of body weight and tested after 60 minutes for whole body 3H-incorporation into fatty acids and triglycerides, or terminated for triglyceride storage content analysis. Fatty acid and triglyceride synthesis (microgram-atoms 3H incorporation/hour/gram of tissue) and triglyceride storage content (milligrams/gram wet weight) for LA/N-fak- (“corpulent”) obese rats were higher (P < 0.05) in gastrocnemius and vastus medius skeletal muscles. Triglyceride storage content was higher (P < 0.05) for obese versus lean animals in iliacus and psoas muscles, inguinal fat, and retroperitoneal fat. Liver fatty acid and triglyceride synthesis and storage content were similar. Fatty acid and triglyceride synthesis and storage content for Zucker fa obese rats were higher (P < 0.05) in vastus medius muscles compared with lean littermates. Triglyceride synthesis in psoas, iliacus, and gastrocnemius muscles, and in liver was higher (P < 0.05) in obese versus lean rats. Obese rats had higher triglyceride storage content (P < 0.05) in soleus and gastrocnemius muscles, liver, inguinal fat, and retroperitoneal fat compared with lean littermates. Because skeletal muscle mass is several times that of liver and because obese rats synthesize significantly more lipids than their lean littermates, we suggest that skeletal muscle may play a substantial role in the development of obesity in both of these rat strains.
Obesity – Research.
Mann, Karin Traci, "In vivo incorporation of tritium to measure lipogenesis in red skeletal muscle: significance of a nonlipogenic diet in LA/N-fa(k)("corpulent") and Zucker fa rat strains" (1997). Theses, Dissertations and Capstones. 1719.
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