ABSTRACT
Sterol fractions were isolated from the hemolymph and hepatopancreasovotestis complex of snails, target [Biomphalaria alexandrina] and non- target [Lymnaea truncatula and Physa acuta] to schistosoma infection. The sterol fractions were identified using GC/MS and also they were investigated in different maturity stages of Biomphalaria alexandrina snails. The results revealed the presence of C[26], C[27], C[28], C[29], and C[30] sterols in tissue extracts and hemolymph or hemocyanin of the three snail species. The probable biosynthetic pathways and metabolism of some of these sterols into various forms present in higher vertebrates were discussed. It is suggested that Biomphalaria alexandrina snails are capable of converting delta[5] sterols into- delta[7] and delta[5,7,22] sterols. Also, the different maturity stages of B. alexandrina snails revealed the possible role of the digestive gland in the interconversion of sterols and the increase in sterol content with sexual maturity. Sterol fractions were investigated by GC/MS from hemolymph and hepatopancreas-ovotestis complex of Schistosoma target [B. alexandrina] and Schistosoma non-target [Lymnaea truncatula and Physa acuta] snails. Also the levels of these sterols were determined in different maturity stages [juvenile, adult, sensent] of B. alexandrina snails