Objective: To clarify the mechanism of the suppressive effect of 2-buten-4-olide (2-B4O), an endogenous feeding suppressant, on the pulsatile secretion of luteinizing hormone (LH), by studying whether endogenous opioid peptides are involved in this suppressive effect. Methods: Using ovariectomized (ovx) rats, blood samples were taken every 6 min for 2 h after administration of 2-B4O or saline into the third cerebroventricle (3V) and sequential i.v. injection of naloxone (0.5 mg/kg per h) or saline. Rats were divided into three experimental groups: group 1: 3V saline þ i.v. saline (control); group 2: 3V 2-B4O þ i.v. saline; group 3: 3V 2-B4O+i.v. naloxone. Serum LH concentrations were determined by double-antibody RIA. To determine whether 2-B4O affected the biosynthetic activity of the opioidergic neurons within the ovx rat arcuate nucleus, we measured the concentrations of pro-opiomelanocortin (POMC) mRNA, a precursor of b-endorphin, in the rostral arcuate nucleus using non-radioactive in situ hybridization and a computerized image-analysis system. Results: 2-B4O significantly suppressed the pulse frequency of LH (group 2: 1.5 Ϯ 0.33 pulses/2 h, group 1: 2.43 Ϯ 0.2 pulses/2 h; P < 0.05), but naloxone blocked its suppressive effect and restored the pulse frequency (group 3: 3.29 Ϯ 0.36 pulses/2 h, group 2: 1.5 Ϯ 0.33 pulses/2 h; P < 0.01). There were no significant changes in the mean LH concentrations and amplitude. Furthermore, 2-B4O significantly stimulated the expression of POMC mRNA in the rostral arcuate nucleus. Conclusion: These results suggest that 2-B4O may impair the pulsatile secretion of LH by activating the opioid pathway within the hypothalamus.

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Background: The survival rate of patients with advanced-stage mucinous cystadenocarcinoma of the ovary is dismal and no best treatment is known. We report a case of complete response of a stage IV mucinous cystadenocarcinoma of the ovary to systemic chemotherapy employing paclitaxel and carboplatin. Case: A 51-year-old nullipara diagnosed with International Federation of Gynecology and Obstetrics stage IV mucinous cystadenocarcinoma of the ovary underwent cytoreductive surgery followed by systemic chemotherapy employing paclitaxel and carboplatin every 4 weeks for 3 courses. The patient tolerated chemotherapy well, demonstrated a remarkable response showing no evidence of malignancy at a second-look laparotomy. As a consolidation chemotherapy after negative second-look laparotomy, she underwent another three courses of chemotherapy of the same regimen, and is showing no evidence of disease. Conclusion: Paclitaxel and carboplatin may be effective in treating mucinous cystadenocarcinoma of the ovary.