Chemosterilization and its reversal in the snail Lymnaea acuminata

Treatment of the snail Lymnaea acuminata, the vector for the liver flukes Fasciola hepatica and Fasciola gigantica, with two alkylating agents (cyclophosphamide and busulfan) and one thiocarbamide (thiourea) caused reduction in the number of eggs and production of non-viable embryos. All the three drugs caused reduction in the levels of DNA, RNA and protein and the activity of alkaline phosphatase in the gonadal tissues of this snail. There was enhancement in free amino acid levels and activity of acid phosphatase by these drugs. Discontinuation of treatment could not reverse the cytotoxic effects of these drugs. Treatment of sterilized snails with prostaglandin E1 (PGE1), prostaglandin F2 alpha (PGF2 alpha) or hydrogen peroxide not only restored the number of eggs but also caused full embryonic development. Also, there was near total recovery of RNA, DNA and protein levels and small changes in free amino acid levels as well as the activity of alkaline and acid phosphatase. It has been suggested that the prostaglandins play a modulatory role in protein synthesis. The possible therapeutic use of PGE1, PGF2 alpha and H2O2 has been pointed out.