Is visceral adiposity a significant correlate of subcutaneous adipose celllipolysis in men?

The aim of the present study was to examine whether site differences in sc adipose tissue (AT) Lipolysis may be considered a contributing factor to th e altered metabolic risk profile of visceral compared to peripheral obese m en once the concomitant variation in adipose cell size is taken into accoun t. For this purpose, sc abdominal and femoral fat cell lipolytic responses were investigated in two groups of men (body mass index, 28 +/- 2 kg/m(2)), aged 36 +/- 3 yr, who were matched for both sc abdominal AT area (256 +/- 64 cm(2)) and sc abdominal adipose cell weight (0.55 +/- 0.08 mu g lipid/ce ll) but were characterized by either a high (162 +/- 29 cm(2); n = 18) or a low (101 +/- 21 cm(2); n = 18) visceral AT deposition. The maximal lipolyt ic response to epinephrine or to isoproterenol (beta-adrenergic agonist) as well as the maximal antilipolytic effect of either epinephrine or clonidin e (alpha(2)-adrenergic agonist) assessed in sc adipocytes were similar amon g men with low us, high levels of visceral AT. However, the beta-adrenocept or sensitivity was increased in sc abdominal adipose cells of individuals w ith a high visceral AT accumulation compared to those with a low intraabdom inal fat deposition. Positive relationships were also found between the Lip olytic sensitivity of sc abdominal adipocytes and plasma insulin concentrat ions measured in the fasting state and after an oral glucose load. These re sults suggest that variation in the degree of visceral adiposity in men doe s not seem to be associated with differences in regional adipose cell maxim al Lipolytic capacity once fat cell size is taken into account. However, th e greater beta-adrenoceptor lipolytic sensitivity of sc abdominal adipocyte s could be considered a significant correlate of the increased insulinemia observed among men characterized by high levels of visceral AT.