DOES MENOPAUSAL STATUS INFLUENCE SEX-STEROID RECEPTOR CONTENT AND SPECIFIC-BINDING CAPACITY

The clinical utility of estrogen and progestin receptors was establish ed initially using ligand binding assays (LBA), which are sensitive to endogenous hormone levels. In this decade, enzyme immunoassay (EIA), which measures receptor content, has become more widely used because t umor biopsy size is often small due to early cancer detection, radiois otopes are not required, and assay turnaround time is shorter. Both LB A and EIA procedures were performed simultaneously on breast biopsies from 252 premenopausal and 219 postmenopausal patients to assess the i nfluence of menopausal status. Estrogen and progestin receptors measur ed by LBA were 2-4 fold higher and 1.5-2 fold higher, respectively, in biopsies from postmenopausal than from premenopausal women. Estrogen and progestin receptor content determined by EIA showed a similar rela tionship. There was a high correlation between LBA and EIA results in biopsies from both premenopausal (r=0.85 for estrogen; r=0.73 for prog estin receptors) and postmenopausal (r=0.91 for estrogen, r=0.89 for p rogestin receptors) women. The relationship between estrogen and proge stin receptor content and specific-binding capacity was not influenced by patient age or menopausal status. These data indicate that regardl ess of the method of receptor determination, the influence of menopaus al status on sex-steroid receptor content and binding capacity is disc ernible (i.e., higher in biopsies from postmenopausal than premenopaus al women).