Depot- and Gender-related Differences in the Lipolytic Pathway of Adipose Tissue from Severely Obese Patients

Abstract

The present study was performed to analyze in detailgender- and site-related alterations in the adrenergicsignal transduction pathway of lipolysis in fat cellsisolated from subcutaneous abdominal and visceralfat depots from severely obese patients. The studygroup consisted of 30 morbidly obese subjects (9 menand 21 women) aged 41.1±1.9 years, with a bodymass index (BMI) of 54.7±1.7 kg/m2, who hadundergone abdominal surgery. Protein levels ofhormone-sensitive lipase (HSL) and adrenergicreceptors (AR), as well as HSL activity and the lipolyticresponse to adrenergic agents were analyzed. Bothfat depots had similar basal lipolysis, but the capacityof catecholamines to activate lipolysis was greater invisceral fat, both at AR and postreceptor levels. Basallipolysis and lipolytic activity induced by dibutyryl cyclicAMP were higher in men than in women. However,the visceral depot of women showed a higher maximalstimulation by noradrenaline than that of men, inaccordance with higher ß1- and ß3-AR protein levels.In conclusion, the main gender-related differenceswere located in the visceral depot, with womenexhibiting a higher sensitivity to catecholaminesassociated with an increased provision of ß-AR, whilemen showed an enhanced lipolytic capacity at thepostreceptor level.