Estrogen receptors in human preadipocytes.

Estrogen influences regional adipose tissue distribution and the accompanying cardiovascular disease risk. To elucidate the mechanisms of this link further, we assessed whether human preadipocytes (PAs) expressed estrogen receptors (ERs) and whether there were any regional or gender differences in ER complement. Human PAs expressed the ERalpha gene but not ERbeta by reverse transcriptase-polymerase chain reaction, possessed ERa protein on Western blotting, and displayed specific 17beta-estradiol (E2) binding with calculated dissociation constants of 0.78 nM, 0.96 nM, and 1.19 nM and maximal binding capacities of 9.3 fmol/mg, 14.6 fmol/ mg, and 18.2 fmol/mg from three whole cell binding assays. There were no regional differences in ERalpha complement for males or females. There were no gender differences in ERalpha complement for subcutaneous or visceral samples. We conclude that ERa but not ERbeta is present in human PAs. This suggests that the effect of estrogen on adipose tissue deposition has a contribution from the direct effect of estrogen on human PAs via ERa.