Reduction of phosphodiesterase 3B gene expression in peroxisome proliferator-activated receptor γ (+/−) mice independent of adipocyte size

Phosphodiesterase 3B (PDE3B) gene expression is generally reduced in large adipocytes of obese, insulin-resistant mice. This reduced gene expression is restored by peroxisome proliferator-activated receptor (PPAR) γ ligands accompanied by a reduced fat cell size. To determine whether PDE3B gene expression is regulated by PPARγ itself, we analyzed lean PPARγ (+/−) mice with adipocyte size comparable to control PPARγ (+/+) mice. In adipocytes of PPARγ (+/−) mice, PDE3B mRNA and protein were both reduced to 63% of wild-type levels. Basal PDE activity tended to be decreased to 70% of wild-type levels, and, similarly, insulin-induced PDE activity was significantly decreased to 70%. Thus, PPARγ is required for PDE3B gene expression independent of adipocyte size. [Copyright &y& Elsevier]