Measuring Tissue Lipid Metabolism In Vivo

For measurements of endogenous triolein clearance rates, tissue-specific lipid-uptake and β-oxidation rates in transgenic tissues, methodologies were adapted from previously detailed studies^{56 (link),57 (link)}. Briefly, ³H-triolein was tail-vein injected (2 µCi/mouse in 100 ul of 5% intralipid) into mice following a 16 h fast. Briefly, blood samples (0.15 ml) were then collected at 1, 2, 5, 10 and 15 min post injection. After 20 min following injection, mice were sacrificed, blood samples were taken and tissues were quickly excised, weighed and frozen at –80 °C until processing. Lipids were then extracted using a chloroform-to-methanol based extraction method^{58 (link)}. The radioactivity content of tissues, including blood samples, was quantified as described previously^{57 (link)}.