Interactions of androgens and estradiol on sex accessory ducts of larval tiger salamanders, Ambystoma tigrinum.
Immature tiger salamander larvae were treated with 12.5 or 25 micrograms of estradiol, testosterone, or dihydrotestosterone (DHT), or 12.5 micrograms of estradiol combined with 12.5 micrograms of either testosterone or DHT. Müllerian duct epithelium was more stimulated by combined steroid treatment than by any steroid alone. Estradiol antagonized the action of DHT in the Wolffian duct. Both of the androgens and estradiol when administered alone at the higher dose stimulated enlargement of connective tissue surrounding the ducts, but the combined 12.5 micrograms androgen/12.5 micrograms estrogen treatment was more effective even though the total steroid administered was the same. The effectiveness of DHT on müllerian cells of this species is evidence against a required aromatization of androgens to explain paradoxical steroid effects and suggests that fundamental differences may exist in steroid receptors of müllerian ducts, connective tissue, and Wolffian ducts. A possible role for the urodele duct system for assessing estrogenic activity of environmental contaminants is discussed.
Norris
D O
DO
Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder 80309-0334, USA.
Carr
J A
JA
Summers
C H
CH
Featherston
R
R
D000557:Ambystoma / Q000254:growth & development*; D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D003238:Connective Tissue / Q000187:drug effects / Q000254:growth & development; D013196:Dihydrotestosterone / Q000494:pharmacology; D004347:Drug Interactions; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008297:Male; D009095:Mullerian Ducts / Q000187:drug effects / Q000254:growth & development*; D013739:Testosterone / Q000494:pharmacology; D014928:Wolffian Ducts / Q000187:drug effects / Q000254:growth & development*
D000728:Androgens; D013196:Dihydrotestosterone; D013739:Testosterone; D004958:Estradiol