Increased concentrations of cathepsin D in peritoneal fluid from women with endometriosis

To assess the release of the proteolytic enzyme cathepsin D in endometriosi s, concentrations in peritoneal fluid and serum were measured by ELISA in 5 4 women with (n = 33) and without (n = 21) endometriosis, Surgery was sched uled in either the proliferative or secretory phase of the menstrual cycle. The concentrations of cathepsin D in the peritoneal fluid were markedly el evated in the endometriosis patients (median 58 ng/ml, interquartile range 0-166 ng/ml) as compared to the controls (5 ng/ml, 0-86 ng/ml), especially in women with late stage disease (It = 19, stages III/IV) and in those not undergoing gonadotrophin-releasing hormone (GnRH) agonist therapy (n = 15), No significant difference was determined in cathepsin D concentrations of the serum from women with and without endometriosis, We conclude that cathe psin D is an important factor that may contribute to the pathogenesis of en dometriosis, possibly by promoting digestion of extracellular matrix protei ns. These results have implications for the therapeutic efficacy of GnRH ag onists.