Gender differences in lipid metabolism are poorly understood and difficult to study using conventional approaches. Magnetic resonance spectroscopy (MRS) permits non-invasive investigation of lipid metabolism. We employed novel two-dimensional MRS techniques to quantify intramyocellular (IMCL) and extramyocellular (EMCL) lipid compartments and their degree of unsaturation in normal weight adult male and female subjects. Using muscle creatine (Cr) for normalization, a statistically significant (p < 0.05) increase in IMCL/Cr (7.8 ± 1.6) and EMCL/Cr (22.5 ± 3.6) for female subjects was observed (n=8), as compared to IMCL/Cr (5.9 ± 1.7) and EMCL/Cr (18.4 ± 2.64) for male subjects. The degree of unsaturation within IMCL and EMCL was lower in female subjects, 1.3 ± 0.075 and 1.04 ± 0.06, respectively, as compared to that observed in males (n=8), 1.5 ± 0.08 and 1.12 ± 0.03, respectively (p < 0.05 male vs female for both comparisons). We conclude that certain salient gender differences in lipid metabolism can be assessed noninvasively by advanced MRS approaches.
Keywords: Extramyocellular lipids; Intramyocellular lipids; Lipid unsaturation; Magnetic Resonance Spectroscopy; Skeletal Muscle.