Insulin Regulation of Lipolysis and Lipolysis Proteins

1. The investigators will determine whether impaired insulin-induced suppression of lipolysis (as measured by IC50) is related to the above mentioned lipolysis proteins in groups of volunteers known to vary widely with regards to abdominal adipocyte size and regulation of adipose tissue lipolysis. 2. The investigators will determine whether the improved insulin regulation of lipolysis resulting from treatment with the PPARγ agonist pioglitazone, with or without weight loss, can be linked to specific changes in sets of PPARγ-responsive adipocyte lipolysis proteins in UBO adults.