1 13c palmitic acid

In the first experiment, male and female mice (n = 3) of both genotypes, wild‐type and Fabp6^−/−, were orally gavaged with olive oil containing 0.05 g/ml of [1‐¹³C]palmitic acid (Sigma Chemical Co.) at 6 ml/kg body weight, housed individually with free access to LFD and water. Stools were collected after 24 h and then stored at −20°C until analysis. In the second experiment, WSD with [U‐¹³C]palmitic acid (CCLM409; Cambridge Isotope Laboratories) (10 μmol/g diet) and was fed over 3 days to individually housed wild‐type and Fabp6^−/− mice (n = 3) of both sexes. Stools were collected every 24 h and stored at −20°C until analysis. Pentadecanoic acid (1 μmol) was added to each stool sample and fat was extracted as described above. Extracted fat was derivatized with pentafluorobenzyl bromide and N,N‐diisopropylethylamine overnight at 4°C. The derivatized fatty acids were extracted and reconstituted in hexane before gas chromatography mass spectrometry analysis (Agilent 5975C) using methane negative chemical ionization and select‐ion monitoring at m/z 256.4, m/z 257.4, and m/z 241.4 for the first experiment, and m/z 256.4, m/z 271.4, and m/z 241.4 for the second experiment.