Gender- and site-related effects on lipolytic capacity of rat white adipose tissue

Abstract

Gender- and site-related differences in the lipolytic capacity, at the different steps of the adrenergic pathway, in gonadal and inguinal white adipose tissue (WAT), were assessed by studying α_2A-adrenergic receptor (AR), β₃-AR and hormone-sensitive lipase (HSL) protein levels, and by determining the lipolytic response to different agents. Gonadal WAT showed a lower α_2A/β₃-AR ratio, a greater lipolytic capacity in response to AR agonists, and higher HSL activity and protein levels than inguinal WAT. In female rats, we found greater α_2A-AR protein levels and α_2A/β₃-AR ratio compared to their male counterparts, but, on the other hand, a higher lipolytic response to β-AR agonists and a greater lipolytic capacity at the postreceptor level, including a more activated HSL protein. Thus, the lipolytic capacity was clearly higher in gonadal than in inguinal WAT, at the different steps of the adrenergic pathway studied. Moreover, in both tissues, females showed a greater inhibition of lipolysis via α₂-AR, which was counteracted by the higher lipolytic capacity at the postreceptor level.