Serum and peritoneal fluid levels of IGF I and II and insulinlike growth binding protein-3 in endometriosis.

OBJECTIVE: To examine whether insulinlike growth factor I (IGF I), IGF II and IGF binding protein 3 (IGFBP 3) in serum and peritoneal fluid (PF) correlate with the presence and severity of endometriosis. STUDY DESIGN: Case-control study including 29 patients with endometriosis and 15 controls. The revised American Fertility Society classification stages of I and II were pooled as early-stage (n = 15), and stages III and IV were taken as late stage (n = 14). Simultaneous sampling of blood and PF was performed during laparoscopy, and IGF I, IGF II and IGFBP 3 levels were determined by immunoradiometric assay. RESULTS: The serum levels of all three proteins were higher than PF levels except for a reversed IGF I PF: serum ratio in the early stage. There were no significant differences in IGF II and IGFBP 3 levels among the groups. The mean serum IGF I levels of controls and early-stage patients were significantly lower than those in the late stage. Also, mean PF IGF I levels in controls were significantly lower than in the late stage. CONCLUSION: IGF I may be an important mediator in the development and/or maintenance of endometriosis or progression to late-stage disease.