Inclusion Criteria:

• Healthy women ages 18 - 45 years.
• Regular menstrual cycles (24-35 days).
• Pelvic pain ≥ 3 months with cyclical component.
• Negative pregnancy test and must use nonhormonal contraception.
• Non-lactating.
• No history of liver disease.
• Consent to participate in the study.
• Endometriosis diagnosed from surgical specimen by routine hematoxylin and eosin staining and histological evaluation within the past 4 years.

Exclusion Criteria:

• Major psychiatric conditions or the abuse of alcohol or drugs which would make it difficult for the subject to complete study procedures.
• Active or prior infection with hepatitis, human immunodeficiency virus (HIV) infection, or history of high-risk activities (e.g., IV drug abuse) which would increase risk to laboratory personnel. Of note, no testing for hepatitis or HIV will be performed as part of this study and all tissues will be handled and discarded as if they were potentially infected.
• Patients with liver dysfunction (elevated liver enzymes > 2 times the upper limit of normal).
• Presence of pre-existing malignancy, including carcinoma of the breast or uterus.
• Women with other causes of chronic pelvic pain including infectious, gastrointestinal, musculoskeletal, neurologic or psychiatric.
• Elevated WBC.
• NYHA functional class I-IV heart failure.
• Diabetics.
• Known pregnancy or positive pregnancy test.