Abstract
In a comparative study of endometriosis and endometrium, specimens were taken from both endometriotic and endometrial tissue in 14 patients. Receptor assays and histological examinations were performed on both specimens. Cy-tosolic estrogen receptors (ERc) as well as cytosolic progesterone receptors (PRc) were detected in 9/14 and 12/12 cases of endometriosis respectively. Nuclear estrogen receptors (ERn) were detected in 4/4 cases of endometrosis. Expressed as fmol/mg cytosol protein, significantly higher values of both ERc and PRc were found in endometrium than endometriosis (p<0.01). However, when the ratio between PRc and ERc was considered, significantly higher PRc/ERc ratios were found in the cytosol of endometriotic tissue (p<0.01). Thus the lower receptor concentrations found in endometriosis cannot be explained solely as ectopic endometrium being diluted by non-receptor-containing tissue. In spite of high PRc/ERc ratios in endometriosis, secretory changes similar to those found in endometrium were observed in only one of 7 cases (p<0.05).