An in vivo study of the cortisol-cortisone shuttle in subcutaneous abdominal adipose tissue

Previous in vitro studies have demonstrated significant 11-beta hydroxysteroid dehydrogenase (11 beta-HSD) oxo-reductase activity in visceral, but not subcutaneous adipose stromal cells. We have conducted an in vivo study of the cortisol-cortisone shuttle in subcutaneous abdominal adipose tissue.

We measured arteriovenous (A-V) differences in serum cortisol and cortisone across subcutaneous abdominal adipose tissue and forearm muscle in a heterogeneous group of subjects.

We studied 34 subjects (male:female = 12:22), age median (interquartile range) 45 (19-65) years, body mass index 32.7 (20.4-77.1) kg m-2, total body fat 34.4 (5.6-119.1) kg.

Serum cortisol and cortisone were measured in serum samples from a radial artery, superficial epigastric vein and deep forearm vein. Abdominal adipose and forearm blood flow rates were measured by 133Xenon washout and plethysmography, respectively.

For cortisone, there was significant (P < 0.001) clearance by adipose tissue, with an A-V difference of 4 (1-7) nmol/l. For cortisol there was a trend for arterial concentrations (203 (142-292) nmol/l) to be lower than venous (225 (152-263) nmol/l), but this was not significant. The adipose tissue cortisone clearance rate correlated with total body fat (r = 0.35, P = 0.05).

We have demonstrated 11 beta-HSD oxo-reductase activity in subcutaneous abdominal adipose tissue, which may be increased in obesity.