The role of enalapril in the prevention of ovarian hyperstimulation syndrome: a rabbit model.

BACKGROUND The purpose of our study was to investigate the role of enalapril in the prevention of ovarian hyperstimulation syndrome. METHODS Twenty New Zealand female rabbits were included in the study. A total of 75 IU FSH + 75 IU LH was given daily by i.m. route for the first 7 days and additionally 2500 IU HCG was given on the last day of ovarian stimulation. Between days 0 and 9, oral enalapril tablets (2 mg/kg) were given twice daily to 10 rabbits (group 1). The remaining 10 rabbits did not receive enalapril (group 2). Laparatomy was performed on all rabbits at day 9. The amount of peritoneal fluid and the weight of the ovaries were recorded during laparotomy. Serum renin, interleukin-6 (IL-6), oestradiol, progesterone, prolactin and aldosterone concentrations were assayed at day 0 and again at day 9 for all rabbits. RESULTS Serum renin and IL-6 concentrations at day 9 increased significantly compared with basal values in both groups (P < 0.05). Renin was correlated with IL-6 at day 9 in both groups (P < 0.05). The amount of peritoneal fluid and the increase in body weight observed at day 9 were not significantly different between groups 1 and 2. Administration of enalapril did not prevent the formation of ascites in group 1 despite the low serum aldosterone concentrations. In group 1 the weight of ovaries was significantly higher than the control group (P < 0.05). CONCLUSIONS Renin-angiotensin system and IL-6 may play a role in the aetiopathogenesis of ovarian hyperstimulation syndrome. Administration of enalapril did not seem to have any beneficial effect in reducing the severity of ovarian hyperstimulation syndrome.