Induction of vitellogenin-like lipoproteins in the mussel Aulacomya ater under exposure to 17ß-estradiol

The mussel Aulacomya ater was exposed to 17ß-estradiol (E2) (0, 1, 100 µg L^-1) for 21 days with 4 sampling periods to evaluate how these organisms deal with exogenous estrogenic compounds. In addition, 2 concentrations of 17ß-estradiol (0.5, 1 mmol) were injected into the abductor muscle of 5 individuals. The effects of E2 were determined by measuring the vitellogenin (Vg) levels with an alkaline labile phosphate (ALP) assay for gonads and using histological analyses. The results show an increment in ALP levels for males exposed to the lowest E2 levels, principally during the first 4 days of exposure, indicating that the response of Vg to E2 is time-dependent. Some differences were observed between the reproductive parameters (gonadosomatic index and maturity) of males and females exposed and unexposed to E2. Clear differences were also found in ALP levels between sexes, with the highest value occurring in male gonads. No response in Vg levels was detected in females after exposure to E2. Our results suggest that the reproductive cycle A. ater may be altered by E2 exposure, which is relevant considering recent reports of high levels of E2 in the sediments off south-central Chile.