Additional info: |
Peroxisome proliferator-activated receptors (PPARs) are ligand activated nuclear receptors. Three PPAR subtypes have been identified: (alpha), (beta) (also called (delta) and NUC1), and (gamma). PPAR(gamma) is the most widely studied PPAR and exists in two protein isoforms ((gamma)1 and (gamma)2) due to use of an alternative promoter and alternative splicing. PPAR(gamma) is primarily expressed in adipose tissue and to a lesser extent in colon, the immune system, and the retina. PPAR(gamma) was first identified as a regulator of adipogenesis, but also plays an important role in cellular differentiation, insulin sensitization, atherosclerosis, and cancer. Ligands for PPAR(gamma) include fatty acids, arachidonic acid metabolites such as 15-deoxy-D12,14-PGJ2, as well as the thiazolidinedione class of compounds (TZD) which include pioglitazone and rosiglitazone. TZDs are potent, selective PPAR(gamma) agonists that lower the hyperglycemia, hyperinsulinemia, and hypertriglyceridemia found in type 2 diabetic subjects and are presently used as oral antidiabetic drugs. The use of these synthetic ligands has increased the understanding of PPAR(gamma) |