In vitro metabolism of androstenedione and identification of endogenous steroids in Helix aspersa

Guellec, Dominique Le; Thiard, M.-C.; Rémy-Martin, Jean-Paul; Deray, A; Gomot, L; Adessi, G. L.

doi:10.1016/0016-6480(87)90253-x

Cited by 62 publications

(24 citation statements)

References 21 publications

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“…lapi]lus. Androstenedione, one of the male sex hormones, can be aromatized to estrogens by molluscs (Le Guellec et al, 1987) and was detected beside progesterone, testosterone, 17B-estradiol, estrone and estriol in H. reticulata by HPLC and radioimmunoassay (Bettin, unpublished results). Androgen action in androgen-sensitive tissues requires the presence of androgen receptors to mediate transcriptional activation.…”

Section: Resultsmentioning

confidence: 99%

TBT-induced imposex in marine neogastropods is mediated by an increasing androgen level

Bettin

Oehlmann

Stroben

1996

Helgolander Meeresunters

299

183

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Tributyltin (TBT) exposure at different concentrations (5, 50, and 100 ng TBT as Sn/1) induces a concentration-and time-dependent imposex (= pseudohermaphroditism) development in female Nucella lapillus and Hinia reticulata. In both species the average imposex stage, termed as vas deferens sequence (VDS) index, and the average female penis length increases with increasing TBT concentration and duration of TBT exposure. Testosterone added at a concentration of 500 ng/1 induces a faster and more intensive imposex development compared to that induced by the TBT concentrations used in the present experiments. Radioimmunological determination of endogenous steroid content reveals increasing testosterone titres in female gastropods exposed to TBT which correlate with the TBT concentration used and the duration of the experiment. The most marked and highest increase of the endogenous testosterone level is exhibited by females of both species exposed to testosterone. Simultaneous exposure to TBT and to the antiandrogen cyproterone acetate which suppresses imposex development completely in N. lapillus and reduces imposex development strongly in H. reticulata proves that the imposex-inducing effects of TBT are mediated by an increasing androgen level and are not caused directly by the organotin compound itself. Furthermore, TBT-induced imposex development can be suppressed in both snails by adding estrogens to the aqueous medium. These observations suggest that TBT causes an inhibition of the cytochrome P-450 dependent aromatase system which catalyses the aromatization of androgens to estrogens. The increase of the androgen content or the shift of the androgen-estrogen balance in favour of androgens induces the development of pseudohermaphroditism in marine prosobranchs. Artificial inhibition of the cytochrome P-450 dependent aromatase system using SH 489 (1-methyl-1,4-androstadiene-3,17-dione) as a steroidal aromatase inhibitor and flavone as a nonsteroidal aromatase inhibitor induces imposex development in N. lapfllus as well as in H. reticulata.

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Section: Resultsmentioning

confidence: 99%

TBT-induced imposex in marine neogastropods is mediated by an increasing androgen level

Bettin

Oehlmann

Stroben

1996

Helgolander Meeresunters

299

183

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“…Numerous studies have examined the ability of gastropods to convert various precursors to progestagens, androgens, and estrogens in vitro and in vivo (Bose et al 1997;de Jong-Brink et al 1981;Gottfried 1970;Gottfried and Dorfman 1969;Gottfried and Dorfman 1970;Gottfried and Lusis 1966;Janer et al 2005aJaner et al , b, 2006aKrusch et al 1979;Le Guellec et al 1987;Lehoux and Williams 1971;Lupo Di Prisco and Dessi' Fulgheri 1975;Lupo Di Prisco et al 1973;Lyssimachou et al 2009;Oberdorster et al 1998;Ronis and Mason 1996;Teshima and Kanazawa 1971). Almost all of the enzyme activities in vertebrate steroidogenesis have been detected in at least one gastropod species indicating that gastropods have the enzymatic machinery for synthesizing sex steroids.…”

Section: Hormones Of the Reproductive Neuro-endocrine Cascadementioning

confidence: 97%

“…Vertebrate-type sex steroids including estrogens (estrone, 17b-estradiol, estriol) and androgens (androstenedione, androsterone, dehydroepiandrosterone) have been definitively identified in gastropods using gas chromatography-mass spectroscopy (GC-MS) (Le Guellec et al 1987). In addition, sex steroids have been quantified via less-specific immunoassays (e.g., radioimmunoassay) in multiple tissues of gastropods (Bose et al 1997;Gooding and LeBlanc 2004;Janer et al 2006b;Kavaliers et al 2000;Le Guellec et al 1987;Sternberg et al 2008a;Takeda 1980). However, the mere detection of sex steroids in a gastropod provides no insight as to whether these biomolecules actually function as hormones in these organisms.…”

Section: Hormones Of the Reproductive Neuro-endocrine Cascadementioning

confidence: 99%

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

et al. 2009

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Prosobranch snails have been afflicted globally by a condition whereby females develop male sex characteristics, most notably a penis. This condition, known as imposex, has been causally associated with the ubiquitous environmental contaminant tributyltin (TBT). Deduction of the mechanism by which TBT causes imposex has been hampered by the lack of understanding of the normal endocrine regulation of reproductive tract recrudescence in these organisms. We have reviewed the relevant literature on the environmental and endocrine factors that regulate reproductive tract recrudescence, sexual differentiation, and reproduction in gastropods. We provide a cohesive model for the environmental-endocrine regulation of reproduction in these organisms, and use this information to deduce a most likely mechanism by which TBT causes imposex. Photoperiod appears to be the predominant environmental cue that regulates reproductive tract recrudescence. Secondary cues include temperature and nutrition which control the timing of breeding and egg laying. Several hormone products of the central and peripheral nervous systems have been identified that contribute to recrudescence, reproductive behaviors, oocyte maturation and egg laying. Retinoic acid signaling via the retinoid X-receptor (RXR) has shown promise to be a major regulator of reproductive tract recrudescence. Furthermore, TBT has been shown to be a high affinity ligand for the RXR and the RXR ligand 9-cis retinoic acid causes imposex. We propose that TBT causes imposex through the inappropriate activation of this signaling pathway. However, uncertainties remain in our understanding of the environmental-endocrine regulation of reproduction in gastropods. Definitive elucidation of the mechanism of action of TBT awaits resolution of these uncertainties.

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“…Haemolymph Le Guellec et al,1987 RIA/IEA Octopus vulgaris Reproductive tissues 1 D' Aniello et al, 1996 Marisa cornuarietis Visceral coil Janer et al, 2006a Bolinus brandaris Visceral coil Ruditapes decussata Whole animal Morcillo et al, 1998 Estradiol RIA…”

Section: Helix Aspersamentioning

confidence: 99%

Sex steroids and potential mechanisms of non-genomic endocrine disruption in invertebrates

2007

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The review reports on the presence and metabolism of sex steroids in several invertebrate species and provides detailed information on possible mechanisms of endocrine disruption other than the interaction with nuclear receptors. The presence of most vertebrate sex steroids in invertebrate tissues has been demonstrated by liquid or gas chromatography coupled to mass spectrometry. In addition, enzymatic pathways involved in the steroidogenic pathway have been described in at least some invertebrate phyla. Some endocrine disruptors induce alterations in these metabolic pathways and might lead to changes in steroid levels. Growing evidence suggests that estradiol can act through non-genomic pathways in molluscs, and that xenobiotics can as well interfere in these signalling cascades. In spite of these recent advances, most question marks on the action and function of sex steroids in invertebrates remain to be answered.

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In vitro metabolism of androstenedione and identification of endogenous steroids in Helix aspersa

Cited by 62 publications

References 21 publications

TBT-induced imposex in marine neogastropods is mediated by an increasing androgen level

TBT-induced imposex in marine neogastropods is mediated by an increasing androgen level

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

Sex steroids and potential mechanisms of non-genomic endocrine disruption in invertebrates

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