Turtle sex determination assay: mass balance and responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3,3',4,4',5-pentachlorobiphenyl.
Polyhalogenated hydrocarbons have been implicated in the anomalous sexual differentiation of mammals and reptiles. Here, a temperature-sensitive turtle sex determination assay using the red-eared slider (Trachemys scripta elegans) was used to determine the estrogenic or antiestrogenic activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3,3',4,4',5-pentachlorobiphenyl (PCB-126). Neither TCDD nor PCB-126 showed a statistically significant difference in the resulting sex ratios (Fisher's exact test, p < 0.45). As a consequence of the dosing technique (eggshell spotting), the shell retained 90 and 96% of the dose for PCB- 126 and TCDD, respectively, similar to retention of estradiol- 17beta. However, the dosing allowed transfer of sufficient chemical to achieve tissue concentrations that were greater than most concentrations reported for environmentally incurred residues. Similar relative mass distributions of PCB-126 and TCDD were observed in albumin (14-20%), yolk (55-70%), and embryo (16-25%). Relative concentration distributions in the embryo approached those in the yolk, 37 to 40% and 40 to 52%, respectively, while relative concentrations in the albumin remained at 11 to 20%. Lipid-normalized TCDD and PCB-126 concentrations were 30- to 40-fold greater in the embryo than in the yolk. It is hypothesized that nonpassive partitioning processes may have occurred in the embryo.
Gale
Robert W
RW
robert_gale@usgs.gov
Bergeron
Judith M
JM
Willingham
Emily J
EJ
Crews
David
D
D000818:Animals; D004530:Egg Yolk / Q000737:chemistry / Q000187:drug effects; D004625:Embryo, Nonmammalian / Q000737:chemistry / Q000187:drug effects; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D005260:Female; D006066:Gonads / Q000737:chemistry / Q000187:drug effects / Q000196:embryology; D007185:Incubators; D008297:Male; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000633:toxicity*; D000072317:Polychlorinated Dibenzodioxins / Q000032:analysis / Q000633:toxicity*; D012732:Sex Determination Analysis; D012733:Sex Differentiation / Q000187:drug effects*; D012744:Sex Ratio; D013696:Temperature; D014426:Turtles / Q000196:embryology*
D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D011078:Polychlorinated Biphenyls; C023035:3,4,5,3',4'-pentachlorobiphenyl