title: Determinants of intramyocellular lipid concentrations in rat hindleg muscle.
abstract: The investigation of intramyocellular lipids (IMCLs) with proton MR spectroscopy ((1)H-MRS) in humans has recently received increasing attention. IMCL levels correlate with insulin resistance and are affected by diet and exercise, making IMCL an interesting marker for metabolic investigations. In the present in vivo study, the feasibility of using (1)H MRS for the detection of IMCL in rats is demonstrated, and the influence of various factors, such as age, gender, muscle type, and rat strain, on IMCL levels is systematically analyzed. In healthy Wistar and Sprague Dawley (SD) rats, the highest ratios of IMCL/tCr were found in young rats, and IMCL/tCr decreased with increasing age. In addition, IMCL concentration was clearly influenced by gender and muscle type. Insulin-resistant, male, obese, Zucker diabetic fatty (ZDF) rats showed significantly higher IMCL levels than Wistar or SD rats. In conclusion, although IMCL levels are clearly influenced by insulin resistance, several other factors influence IMCL levels, such as age, gender, muscle type, and rat strain. Therefore, when using IMCL as a surrogate marker for insulin resistance, it is necessary to carefully compare results with age- and gender-matched controls, and to use identical conditions.
authors.affiliation: Aventis Pharma Deutschland GmbH, Frankfurt, Germany. Claudia.Neumann-Haefelin@aventis.com
authors.forename: Claudia
authors.initials: C
authors.lastname: Neumann-Haefelin
authors.forename: Johanna
authors.initials: J
authors.lastname: Kuhlmann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Belz
authors.forename: Juergen
authors.initials: J
authors.lastname: Kalisch
authors.forename: Manfred
authors.initials: M
authors.lastname: Quint
authors.forename: Martin
authors.initials: M
authors.lastname: Gerl
authors.forename: Hans-Paul
authors.initials: HP
authors.lastname: Juretschke
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Herling
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D005260:Female; D006614:Hindlimb; D007333:Insulin Resistance; D008055:Lipids / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000737:chemistry; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000166:cytology; D009765:Obesity / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011924:Rats, Zucker
chemical_list: D008055:Lipids