Effect of cadmium on gonadogenesis and metamorphosis in Pleurodeles waltl (urodele amphibian).
In the amphibian Pleurodeles waltl, steroid hormones play a key role in sex differentiation. Since cadmium has been reported to block receptors of sex steroid hormones, we analyzed the effects of this heavy metal on Pleurodeles larvae gonadogenesis. At stage 42, larvae die in the presence of 10.9 microM Cd in the rearing tap water, with TL(50) of 46.3 h, but the concentration of 5.5 microM is tolerated for more than 60 days. When used at 5.5 microM cadmium accumulation measured by atomic absorption spectrophotometry (AAS) in total homogenates of larvae at stage 54 (after 77 days of exposure to the heavy metal) reached 58.1 microg/g of dry weight. At stage 54, we did not detect inhibitory effects on gonadogenesis in larvae reared in the presence of 5.5 microM Cd since stage 42. When the exposure to 5.5 microM Cd was lengthened after stage 54, metamorphosis was delayed and could not be completed. When larvae were exposed to 10.9 microM Cd from stage 54, metamorphosis did not occur and gonad development was stopped. Our study demonstrates a lack of a direct effect of cadmium on sex determination-differentiation but a strong inhibitory effect on metamorphosis, which impairs further gonadal development.
Flament
S
S
Faculté des Sciences, EA3442 Génétique, Signalisation, Différenciation, Université Henri Poincaré, Entrée 1B, 9ème étage, Boulevard des Aiguillettes, BP 239, 54506 Vandoeuvre-les-Nancy cedex, France. stephane.flament@scbiol.uhp-nancy.fr
Kuntz
S
S
Chesnel
A
A
Grillier-Vuissoz
I
I
Tankozic
C
C
Penrad-Mobayed
M
M
Auque
G
G
Shirali
P
P
Schroeder
H
H
Chardard
D
D
D000704:Analysis of Variance; D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000633:toxicity; D005260:Female; D012739:Gonadal Steroid Hormones / Q000037:antagonists & inhibitors; D006066:Gonads / Q000187:drug effects*; D006727:Hormone Antagonists / Q000633:toxicity*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D007928:Lethal Dose 50; D008297:Male; D008675:Metamorphosis, Biological / Q000187:drug effects*; D038081:Organogenesis / Q000187:drug effects*; D010999:Pleurodeles / Q000033:anatomy & histology / Q000254:growth & development*; D012732:Sex Determination Analysis; D012733:Sex Differentiation / Q000187:drug effects*; D013997:Time Factors
D004785:Environmental Pollutants; D012739:Gonadal Steroid Hormones; D006727:Hormone Antagonists; D002104:Cadmium