Adiponectin cDNA was cloned into AAV serotypes 1, 2, and 5-based expression vectors. Virions containing these vectors were administered to the livers of rat subjects via portal vein injection. A single injection of 610¹¹ virions of the vector caused a sustained and statistically significant reduction in body weight of the treated animals compared to the control animals. This occurred in the absence of side effects. Compared to control animals, the subject rats also exhibited reduced adipose tissue mass, reduced appetite, improved insulin sensitivity, and improved glucose tolerance.