Steroid hormone receptors in human adipose tissues

Administration of glucocorticoid, estrogen, and progesterone is followed by changes in human adipose tissue distribution, morphology, and function. Therefore, specific receptors for these hormones were determined in different regions of human adipose tissue using ligand techniques, with separation of bound and free hormone by chromatography, absorption techniques, or isoelectric focusing, as well as protein quantitation with monoclonal antibodies against human estrogen and progesterone receptors. Furthermore, mRNAs were measured by solubilization hybridization technique with glucocorticoid, estrogen, and progesterone receptor cRNA probes for human receptors. Saturable specific cytosolic glucocorticoid binding was found. Quantitative analyses indicated more binding sites and mRNAs in intraabdominal than sc adipose tissue samples. In contrast, neither specific estrogen or progesterone binding, cytosolic or nuclear receptor protein, nor mRNAs for these receptors could be identified in abdominal, femoral, or omental adipose tissues. Parallel control experiments confirmed the presence of both estrogen and progesterone receptors in rat adipose tissues. It was concluded that while glucocorticoid receptors are clearly present in human adipose tissues, female sex hormone receptors are not present in quantities detectable with presently available methods. Effects of these hormones on human adipose tissue might, therefore, be mediated via a minute nondetectable quantity of receptors, the glucocorticoid receptor, or indirect mechanisms.