Nonylphenol (NP) is known for its estrogenicity to aquatic organisms, fish in particular, it being able to mimic the action of endogenous estrogens. As a consequence, NP can induce vitellogenin (Vg) synthesis, the major precursor of the egg-yolk proteins. In the present study, NP estrogenicity was evaluated in both sexually undifferentiated (resting phase) and differentiated (pre-spawning phase) cockles (Cerastoderma glaucum) after exposure for 7 and 14 days to 0, 0+acetone, 0.0125, 0.025, 0.05, and 0.1 mg NP/L. Vg levels were determined in both haemolymph and digestive gland by the alkali-labile phosphate (ALP) assay. In the resting phase of animals, exposure for 7 days to 0.1 mg NP/L resulted in significant increases in ALP in both haemolymph and digestive gland with respect to controls. A significant increase was also shown in digestive gland from 0.0125 mg NP/L-exposed animals. After 14-days exposure, haemolymph ALP levels significantly increased at all NP concentrations tested, whereas no difference was recorded in digestive gland. In the pre-spawning phase of cockles, exposure for 7 days to NP significantly increased ALP levels in haemolymph from males at all NP concentrations tested, whereas no significant variation were found in haemolymph from females. NP (0.05 and 0.1 mg/L) was also shown to increase significantly ALP concentrations in digestive gland from males, but not in those from females. Likewise, after 14 days exposure, ALP levels significantly increased in haemolymph from males only (at 0.1 mg NP/L). Conversely, NP caused significant increases in ALP levels in digestive gland from both males (at all NP concentrations tested) and females (at 0.025 and 0.1 mg NP/L). Results obtained demonstrates that NP induces Vg synthesis in C. glaucum both far from the reproductive period (resting phase) and in pre-spawning phase of animals. In the latter case, males were more responsive to NP than females. As endocrine disruption may cause fertility reduction and alteration in sex ratio, a condition of potential risk for cockle populations in estuarine areas is highlighted. Acknowledgement This study was supported by grants from Co.Ri.La (Consortium for Coordination of Research Activities Concerning the Venice Lagoon System, Second Research Programme, 2004-2006).

VITELLOGENIN INDUCTION IN THE COCKLE CERASTODERMA GLAUCUM AFTER EXPOSURE TO 4-NONYLPHENOL

MARIN, MARIA;MATOZZO, VALERIO
2007

Abstract

Nonylphenol (NP) is known for its estrogenicity to aquatic organisms, fish in particular, it being able to mimic the action of endogenous estrogens. As a consequence, NP can induce vitellogenin (Vg) synthesis, the major precursor of the egg-yolk proteins. In the present study, NP estrogenicity was evaluated in both sexually undifferentiated (resting phase) and differentiated (pre-spawning phase) cockles (Cerastoderma glaucum) after exposure for 7 and 14 days to 0, 0+acetone, 0.0125, 0.025, 0.05, and 0.1 mg NP/L. Vg levels were determined in both haemolymph and digestive gland by the alkali-labile phosphate (ALP) assay. In the resting phase of animals, exposure for 7 days to 0.1 mg NP/L resulted in significant increases in ALP in both haemolymph and digestive gland with respect to controls. A significant increase was also shown in digestive gland from 0.0125 mg NP/L-exposed animals. After 14-days exposure, haemolymph ALP levels significantly increased at all NP concentrations tested, whereas no difference was recorded in digestive gland. In the pre-spawning phase of cockles, exposure for 7 days to NP significantly increased ALP levels in haemolymph from males at all NP concentrations tested, whereas no significant variation were found in haemolymph from females. NP (0.05 and 0.1 mg/L) was also shown to increase significantly ALP concentrations in digestive gland from males, but not in those from females. Likewise, after 14 days exposure, ALP levels significantly increased in haemolymph from males only (at 0.1 mg NP/L). Conversely, NP caused significant increases in ALP levels in digestive gland from both males (at all NP concentrations tested) and females (at 0.025 and 0.1 mg NP/L). Results obtained demonstrates that NP induces Vg synthesis in C. glaucum both far from the reproductive period (resting phase) and in pre-spawning phase of animals. In the latter case, males were more responsive to NP than females. As endocrine disruption may cause fertility reduction and alteration in sex ratio, a condition of potential risk for cockle populations in estuarine areas is highlighted. Acknowledgement This study was supported by grants from Co.Ri.La (Consortium for Coordination of Research Activities Concerning the Venice Lagoon System, Second Research Programme, 2004-2006).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2485165
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