Characterization of regional and gender differences in glucocorticoid receptors and lipoprotein lipase activity in human adipose tissue.

Abstract

Glucocorticoid receptor (GR) status was studied in adipose tissue from omental and sc abdominal adipose tissue. As the effects of glucocorticoids may be due to alteration of triglyceride uptake in adipose tissue, the activity of the enzyme lipoprotein lipase (LPL) was also investigated. Fat biopsies were obtained from 8 women and 11 men matched for age and body mass index. Omental adipose tissue contained 4 times the number of GR as sc abdominal adipose tissue (42.0 +/- 4.1 vs. 10.5 +/- 2.3 fmol/mg protein, respectively; P < 0.001) with similar Kd values. No gender difference in GR number was observed in adipose tissue from the two regions. LPL activity in omental adipose tissue was about 820 nmol FFA/h.g wet wt in both sexes, whereas LPL activity in sc adipose tissue was about 2- to 4-fold lower. Moreover, LPL activity in sc adipose showed marked gender differences, with 2-fold higher activity in women than in men (474 +/- 84 vs. 238 +/- 35 nmol FFA/h.g wet weight; P < 0.03). Finally, there was no correlation between GR number and LPL activity when each fat depot was investigated separately. However, a positive correlation between LPL activity and glucocorticoid binding was found when the data from both regions were pooled (r = 0.55; P < 0.01). In conclusion, human adipose tissue dexamethasone binding was higher in omental than in sc adipose tissue, without any gender difference. LPL activity was also higher in omental than in sc adipose tissue in both groups, without any gender difference. On the other hand, sc LPL activity was higher in females than in men. A correlation (positive) between GR number and LPL activity was only found when the data from both regions were pooled.