Core 2 – Lipid Mass Spectrometry provides multiple essential services to every investigator involved with this Program Project Grant. These services include lipid analysis measurements as well as novel and unique lipid measurements that provide unparalleled and comprehensive data providing insight into lipid metabolism. The Core is directed by Dr. Jeff McDonald, who has led the lipid mass spectrometry efforts at UT Southwestern for 17 years. Services include mass spectrometry-based quantification of individual lipid species including sterols, oxysterols, sphingolipids, steroids, bile acids, and fatty acids. Qualitative or semi-quantitative analysis of all lipid classes can be measured providing relative comparisons between sample groups and fatty acid compositions for cholesteryl esters, glycerolipids, and other lipid classes. Unique lipid mass spectrometry measurements center around use of ultra-high resolution mass spectrometry to distinctly measure deuterium incorporation into lipids instead of mathematically deconvoluting 2H signals which overlap with the naturally occurring 13C isotope mass envelope. Using this method results in a signal-to-noise ratio that was at best 1 or 2 using traditional mass spectrometry (unit resolution) techniques to a signal-to-noise of 1000 or greater. This requires very advanced mass spectrometers, two of which are currently in our facility. Coupled with advanced chromatography methods that resolve lipids and lipid classes, the synthesis and flow of lipids through a designated biosynthetic or catabolic pathway in cultured cells and living animals is now feasible. The complex and expensive equipment needed to provide these services include multiple mass spectrometers, a liquid handling robot for sample preparation, 96-well SPE and nitrogen blow-down manifolds for sample processing. The lipid mass spectrometry measurements provided by Core 2 will play a major role in every specific aim in this Program Project and in every publication that arises from the completed research.