Regional and gender variations in adipose tissue lipolysis in response to weight loss

Abstract

Catecholamine-induced lipolysis was investigated in 32 obese subjects (14 men and 18 premenopausal women), aged 36-50 years, whose body mass index ranged from 30 to 42 kg/m 2 . Isolated subcutaneous (subc) abdominal and femoral adipocytes were studied before and after a 15-week weight reducing program, during which mean body weight loss averaged 9 vs. 10 kg in women and men, respectively ( P Ͻ 0.0001). Participants were re-examined when they were weight-stable. Fat cell weight decreased by about 15-20% in both depots ( P values ranging from 0.01 to 0.05). Epinephrine (mixed ␣ 2-/ ␤ -adrenoceptor (AR) agonist) induced antilipolysis at low concentrations and a net lipolytic response at higher doses, irrespective of subjects' fatness and anatomic location of fat. Basal lipolysis, maximal lipolytic responses to isoprenaline ( ␤ -AR agonist), dobutamine and procaterol ( ␤ 1-and ␤ 2-AR agonists, respectively) as well as maximal antilipolytic effects of epinephrine or UK-14304 ( ␣ 2-AR agonist) were similar before and after weight reduction. However, both ␤ -and ␤ 2-AR lipolytic sensitivities and the ␤ -AR density were increased in both genders after weight reduction, this effect being more marked in subc abdominal than in femoral adipocytes ( P values ranging from 0.001 to 0.05). The ␣ 2-AR antilipolytic sensitivity was reduced in adipose cells from both regions in women, but only in subc abdominal adipocytes in men ( P Ͻ 0.05), although the ␣ 2-AR density remained unchanged after weight reduction. In conclusion, a moderate weight loss leads to a higher adipose cell lipolytic efficiency which is associated with changes at receptor levels (mainly an increased ␤ 2-and a decreased ␣ 2-AR sensitivities), in both genders.

Impact of Bariatric Surgery on Adipose Tissue Biology

“…Interestingly, after substantial BS-induced weight loss, the lipolytic effect of isoproterenol stimulation of adrenergic receptors was higher than lean controls, despite no difference in receptor density between groups. Similar results have been reported after short-term nutrition interventions [ 107 , 108 ]. Fasting FFA circulating levels are other relevant measures of basal lipolysis, though they are not only dependent on WAT lipolysis but also on clearance by muscle and the liver.…”

Regional fat mobilization and training type on sedentary, premenopausal overweight and obese women

“…Our results show significant reductions on the relative contribution of TrFM to whole body FM and increases in LLsFM, ULsFM, and HFM. These data confirm the selective fat mobilization from trunk in women (2,5). Furthermore, we found similar effects across protocols thus confirming the classical theory that says that exercise promotes adrenergic stimulation to support muscle contraction energy expenditure (37).…”

“…It is well recognized that fat distribution influences lipid metabolism (5,6,33). Moreover, FFM changes by segments follow different patterns as a consequence of specific resistance training protocol (34).…”

“…It is well recognized that obesity-related disorders are associated with regional fat distribution independently of total body fat (TBF) (1,2). Indeed, metabolic differences have been shown between regional fat depots (3,4), across gender (5) and within the same gender but of different regional phenotype (upper or lower fat distribution) (6). Besides FM, fat free mass (FFM) is another indirect determinant of obesity, as it is the main predictor of resting metabolic rate (RMR) (7).…”

The effects of caloric restriction on adipose tissue and metabolic health are sex- and age-dependent

“…2H-I, S4). The situation in humans differs slightly: CR enhances WAT lipolysis in both sexes but females resist this effect (38). Together, these differences in lipid metabolism likely explain why fat loss in young females is absent or blunted during CR.…”