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Reduction of intramyocellular fatty acid levels after weight loss is not correlated with improvement in insulin sensitivity in the obese
Author(s) -
Stylianopoulos Chryssanthi L,
Horska Alena,
Brown Todd T,
Caballero Benjamin
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a586-c
Subject(s) - insulin resistance , medicine , endocrinology , weight loss , skeletal muscle , adipose tissue , insulin , homeostasis , fatty acid , chemistry , obesity , biochemistry
Previous studies have shown a correlation between intracellular free fatty acid concentrations in skeletal muscle cells and insulin resistance. We hypothesized that a reduction in intramyocellular lipid (IMCL) will have a more significant effect on insulin resistance than a reduction in body adipose tissue stores. Ten healthy obese subjects (BMI=34.14 ± 0.92 [mean ± SE] kg * m −2 , PAL=1.4 ± 0.3) were studied before and after weight loss of 10% initial weight. Insulin resistance (by the Homeostasis Model Assessment [HOMA] index) and intramyocellular lipids in the tibialis anterioris (TA) and soleus (SOL) muscles (by proton nuclear magnetic resonance spectroscopy) were measured at baseline and upon reaching the target weight loss. Weight loss resulted in a 36.5% decrease in insulin resistance by HOMA (p=0.005). IMCL was also significantly reduced by 22% (p<0.05) in the TA but not in the SOL muscle. There was no correlation between changes in IMCL in TA myocytes and in insulin resistance. These results indicate that weight loss is associated with selective reduction of IMCL stores in TA but not SOL myocytes. We found no correlation of this reduction with insulin resistance in this population. Supported by GCRC award M01‐RR00052 from the NCRR/NIH and by USDA award 58‐1235‐2‐060.