title: Dose verification after topical treatment of alligator (Alligator mississippiensis) eggs.
abstract: Numerous studies have used temperature-dependent sex determination in reptilian eggs to investigate potential developmental effects of exogenously applied substances. However, few studies have measured the dose carried across the eggshell. We report embryonic mortality and internal egg concentrations determined by gas chromatography-mass spectrometry two weeks after exposure of American alligator (Alligator mississippiensis) eggs to chlorinated organic pesticides via injection or topical application. Puncturing the eggshell for injection produced high mortality compared with unpunctured controls; therefore, further evaluation of this method was abandoned. Although higher than controls, mortality was much lower in eggs treated topically than in those injected. Transfer of chemicals across the eggshell was very low, highly variable, and did not correlate with the applied dose after topical application. These results are consistent with previous reports in the literature, casting doubt on whether a reproducible internal dose can be achieved in reptilian eggs by topical treatment.
authors.affiliation: Applied Pharmacology and Toxicology Inc., 2250 Northwest 24th Avenue, Gainesville, Florida 32605, USA.
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Muller
authors.forename: Janet E
authors.initials: JE
authors.lastname: Scarborough
authors.forename: María S
authors.initials: MS
authors.lastname: Sepúlveda
authors.forename: George
authors.initials: G
authors.lastname: Casella
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Gross
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Borgert
mesh_terms: D000287:Administration, Topical; D000489:Alligators and Crocodiles / Q000378:metabolism*; D000818:Animals; D004528:Egg Shell / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006843:Hydrocarbons, Chlorinated / Q000008:administration & dosage / Q000633:toxicity*; D007267:Injections; D018811:Maternal Exposure; D009026:Mortality; D010063:Ovum / Q000187:drug effects* / Q000378:metabolism; D010575:Pesticides / Q000633:toxicity*
chemical_list: D006843:Hydrocarbons, Chlorinated; D010575:Pesticides