Peritoneal fluid levels of immunoreactive corticotropin-releasing factor (CRF) and CRF-binding protein (CRF-BP) in healthy and endometriosic women

Corticotropin-releasing factor (CRF) is a 41-amino acid neurohormone involved in the neuroendocrine response to stress, also playing a role in cell-mediated immune functions and in inflammation. In the light of recent evidence showing an association between endometriosis and altered cellular immunity factors, the present study investigates immunoreactive (ir) CRF in the peritoneal fluid of healthy women, and in patients with pelvic adhesions and endometriosis. In addition, peritoneal fluid concentrations of CRF-binding protein (CRF-BP), a 37-kDA protein of 322 amino acids able to modulate central and peripheral CRF functions, were evaluated. Peritoneal fluid samples (n=35) were collected from healthy women (n=12), from patients with intrapelvic adhesions (n=8), and from women with endometriosis (n=15). In the control group a specimen of blood was collected. Peritoneal fluid and plasma CRF levels were measured by a two-site immunoradiometric assay (IRMA), and CRF-BP levels were measured by a specific radioimmunoassay (RIA). CRF and CRF-BP levels in peritoneal fluid were lower than plasma values, and independent of the phase of the menstrual cycle: in particular, in healthy women there was no significant difference between peritoneal fluid and plasma CRF-BP levels during two phases of the menstrual cycle. Peritoneal fluid levels of CRF and CRF-BP were similar in healthy patients and women with pelvic adhesions or with endometriosis, and when patients with adhesions or with endometriosis were considered as single group, no difference in CRF and CRF-BP levels was noted in comparison to the control group. In patients with endometriosis, no significant differences in peritoneal fluid CRF or CRF-BP levels were recorded, although in patients with stage 2 and stage 3 of the disease peritoneal fluid CRF-BP levels were higher than in healthy patients or in those with a lower grade of the disease. These results suggest that the peritoneal concentration of these hormones may reflect the circulating levels: the absence of any significative variations in peritoneal fluid CRF levels according to the degree of the endometriosis, suggests a limited role of CRF in the immunological changes related to the disease.