Endocrine disruption in aquatic pulmonate molluscs: few evidences, many challenges

Abstract

As compared to other groups of aquatic gastropods, documented examples of endocrine disruption in pulmonates are rather limited. This is quite surprising because the endocrine control of physiological functions has been extensively studied in these animals. In the model-species Lymnaea stagnalis, the neurohormonal regulation of reproduction has been thoroughly investigated, and the primary structure of several peptides and receptors involved in endocrine processes has been established. However, the use of this knowledge has been fairly limited in the context of ecotoxicology, to investigate the effects of endocrine-disrupting chemicals. The present review summarizes the main and more recent findings on the neuroendocrine control of reproduction in aquatic pulmonate snails (Basommatophora). It then comprehensively describes selected in vivo laboratory and semi-field studies which provide evidence for possible endocrine disrupting effects of estrogenic and androgenic test compounds [e.g., ethynylestradiol, methyltestosterone (MT)], and of environmental contaminants [e.g., cadmium (Cd), tributyltin (TBT), and nonylphenol (NP), pesticides]. Finally, challenging perspectives for future research are discussed.

Environmental-endocrine control of reproductive maturation in gastropods: implications for the mechanism of tributyltin-induced imposex in prosobranchs

“…Consequently, hormonal control of reproductive physiology in molluscs seems to be heavily dependent upon neurohormones, specifically neuropeptides . Indeed, evaluations of molluscan reproductive endocrinology have focused largely on the neuropeptides that control egg production, oviposition, male copulatory behavior, and protandric sex reversal in gastropods (Table 1; Geraerts et al 1988;Joosse 1988;Lagadic et al 2007;Linacre et al 1990;Saunders et al 1992;Vreugdenhil et al 1988).…”

Endocrine disruption in prosobranch molluscs: evidence and ecological relevance

“…The hormone system of molluscs has been characterized as being the perhaps most diverse of all invertebrate phyla because it differs not only between classes but also within a class, as shown for the gastropods (prosobranchs, pulmonates, and opisthobranchs), reflecting extreme differences in physiology and life histories Lagadic et al 2006). Ecdysteroids like ecdysone, and terpenoids such as juvenile hormone, are reported but a functional role for both is questioned.…”

Development of partial life-cycle experiments to assess the effects of endocrine disruptors on the freshwater gastropod Lymnaea stagnalis: a case-study with vinclozolin

“…The fresh/brackish-water mesogastropod Potamopyrgus antipodarum and the freshwater gastropod Lymnaea stagnalis can be considered as promising candidates to develop toxicity test procedures, which could eventually form the basis of forthcoming international guidelines (Matthiessen 2008). Furthermore, L. stagnalis currently appears as a good candidate to investigate possible modes of action of EDs because the endocrine system has been more largely investigated in this species than in other snails (Lagadic et al 2007). However, there is a need for optimization and validation of toxicity test procedures with this snail before it can be routinely used in higher-tier protocols for the ecological risk assessment of EDs.…”