This book covers a wide range of state-of-the-art methodologies and detailed protocols currently used to study the actions that lipid-activated nuclear receptors and their co-regulators have in tissues and immune cell types considered classic metabolic "powerhouses". This includes the liver, adipose tissue, and monocytes/macrophages present in these and other metabolic tissues. While the main focus is on the oxysterol receptor or Liver X Receptor (LXR), the majority of the methods described can be easily applied to multiple nuclear receptors, as well as to other tissues or cell types. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls.