Estrogen inhibits caudal progression but stimulates proliferation of developing müllerian ducts in a turtle with temperature-dependent sex determination.
Müllerian duct development appears to be similar in many vertebrate groups, and previous studies have shown that this development is estrogen sensitive. For example, embryonic exposure to diethylstilbestrol (DES) in humans and mice, and estrogen exposure in chickens, can have multiple, usually adverse, effects on müllerian duct differentiation and growth. The current study investigates 17beta-estradiol's effects on müllerian duct development in a reptile, the turtle Trachemys scripta. In T. scripta, normal müllerian duct development proceeds cranially to caudally over developmental stages 15 to 21. To ascertain 17beta-estradiol's effect on this process, four groups of eggs were incubated at a female-producing temperature. Each group was treated with 50 mug of 17beta-estradiol or a vehicle control at one of four stages (15, 17, 19, 21). The degree of müllerian duct development was assessed by examining gross morphology and histology. Results showed that estradiol-17beta blocked development of the müllerian duct if applied before differentiation began. If applied afterwards, 17beta-estradiol caused hypertrophy in the differentiated portion, but prevented further differentiation of the müllerian duct in more caudal regions. Therefore, reptilian müllerian ducts in T. scripta are estrogen sensitive and estrogen's effects may be similar to those reported for birds.
Dodd
Keela L
KL
Department of Pharmacology and Toxicology, University of Alabama at Birmingham, 1670 University Blvd, Volker Hall Rm 103, Birmingham AL 35294, USA. kdodd@uab.edu
Wibbels
Thane
T
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006066:Gonads / Q000166:cytology / Q000187:drug effects / Q000196:embryology; D008297:Male; D009095:Mullerian Ducts / Q000166:cytology / Q000187:drug effects* / Q000196:embryology*; D010063:Ovum / Q000166:cytology / Q000187:drug effects; D019849:Sex Determination Processes; D014426:Turtles / Q000196:embryology*
D004958:Estradiol