Secretory cholinesterase of Ancylostoma ceylanicum: effect of tubulin binding agents and benzimidazole anthelmintics.

Ancylostoma ceylanicum, the human hookworm parasite, exhibited significant secretion of cholinesterase when maintained in vitro in RPMI-1640 medium. Secretion of the enzyme was linear up-to 4 hours of incubation. About 40 percent of the total cholinesterase activity was localized in the soluble fraction, while remaining activity was associated with the particulate fraction of the nematode. Exposure of the hookworms to colchicine in vitro caused significant inhibition in secretion of the enzyme by the parasite with concomitant accumulation of cholinesterase within the adult worms. Vinblastine did not show noticeable effect on the enzyme secretion as well as activity within the parasite. Incubation of hookworms with some benzimidazole anthelmintics viz., mebendazole or albendazole significantly reduced the capacity of the worms to secrete cholinesterase and increase in enzyme activity within the parasite. Adult worms recovered from mebendazole treated hamsters exhibited about 3 fold greater activity of cholinesterase as well as significantly lower capacity to secrete cholinesterase in vitro as compared to the worms recovered from untreated animals. These observations indicate role of microtubules in the secretion of cholinesterase by hookworms and as a target for the action of benzimidazole anthelmintics.