A quantitative study of the androtrophic effect (“imposex”) of an organotin and of other metal compounds on females of an ampullariid snail.

GIRAUD-BILLOUD M, VEGA IA, CARRION AM, CASTRO-VAZQUEZ A.

San Luis, Argentina

Congreso; XXVII Reunión Anual de la Sociedad de Biología de Cuyo; 2009

Sociedad de Biología de Cuyo

Some methals such as tributyltin (TBT) but no others compounds are known to induce development of male-like penes in females (“imposex”) in neogastropod species. The architaenioglossan ampullariid snail Pomacea canaliculata differs from neogastropods in that females normally bear rudimentary homologues of male copulatory organs. In the current study, we have quantitatively assessed the androtrophic potential of metal levels on or below the maximum concentrations allowed in drinking water by government regulations: tin, 22 ng/L (as TBT), mercury, 2 µg/L (as HgCl2), arsenic, 10 µg/L (as AsO4Na3) and uranium (as UO2). For such purpose, either none or one of those metal compounds were added to the artificial aquarium water and the animals were exposed for 30 days, and sacrificed at either 4, 5, 6 or 7 months old. Only the organotin had a definite trophic action on the female copulatory organs as shown by a significant increase in penis length and in the “vas deferens sequence index” (a usual measure of imposex) in the 4, 5 and 6 months old females (P<0.05, Kruskal-Wallis/Dunn tests). However, no significant differences were observed in the 7 months old groups, since 7 months control females already had well grown copulatory organs. It is concluded that the age of the animal is an important parameter to be considered when assessing androtrophic actions on females.