Anti-ovulatory activity of H2 receptor blockers in albino rabbits--a preliminary study

Abstract

Objective: To evaluate the anti-ovulatory activity of H(2) receptor blockers (ranitidine, famotidine and roxatidine) in albino rabbits considering the role of histamine in ovulation.

Method: The drugs were orally administered once daily for three days to adult female rabbits weighing between 1.3-2.0 kg (four groups of three animals). The control group received the 1% weight/volume gum acacia suspension. Thirty minutes after the administration of the last dose, a freshly prepared 0.4 % solution of cupric acetate was administered to each animal intravenously via the marginal ear vein (4 mg/kg body weight) to induce ovulation. To assess ovulation, laparotomy was carried out 48 h after cupric acetate injection. The ovaries were exposed, bleeding points on each ovary were counted, and the ovaries and uteri were subjected to histopathological evaluation.

Results: Based on the number of bleeding points (ovulation sites) observed on the ovary, H(2) blockers showed varying degrees of anti-ovulatory activity. Roxatidine exerted the most pronounced activity. Histopathological observations of uterus and ovary confirmed the aforementioned observations.

Conclusion: H(2) receptor blockers appeared to inhibit the cupric acetate-induced ovulation in albino rabbits. Our results seem to confirm the role of histamine in ovulation reported by other authors.