Adipocytes/enzymology; Matrix Metalloproteinases/genetics; Obesity/metabolism; Obesity/physiopathology; Phenylalanine/analogs & derivatives; Thiazolidinediones; Adipocytes/cytology; Animals; Blood Vessels/cytology; Blood Vessels/enzymology; CCAAT-Enhancer-Binding Protein-beta/genetics; Cell Differentiation/physiology; Diet; Disease Models, Animal; Gene Expression Regulation, Enzymologic; Hypoglycemic Agents/pharmacology; Male; Matrix Metalloproteinase 12; Matrix Metalloproteinase 2/genetics; Matrix Metalloproteinase 3/genetics; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases, Membrane-Associated; Matrix Metalloproteinases, Secreted; Metalloendopeptidases/antagonists & inhibitors; Metalloendopeptidases/genetics; Mice; Mice, Inbred AKR; Mice, Inbred C57BL; Mice, Obese; Mitosis/drug effects; Mitosis/physiology; Obesity/genetics; Phenylalanine/pharmacology; Protease Inhibitors/pharmacology; RNA, Messenger/analysis; Rosiglitazone; Stromal Cells/cytology; Stromal Cells/enzymology; Thiazoles/pharmacology; Thiophenes/pharmacology; Tissue Inhibitor of Metalloproteinase-1/genetics; Tissue Inhibitor of Metalloproteinase-3/genetics