title: The rodent estrous cycle: characterization of vaginal cytology and its utility in toxicological studies.
abstract: While an evaluation of the estrous cycle in laboratory rodents can be a useful measure of the integrity of the hypothalamic-pituitary-ovarian reproductive axis, it can also serve as a way of insuring that animals exhibiting abnormal cycling patterns are disincluded from a study prior to exposure to a test compound. Assessment of vaginal cytology in regularly cycling animals also provides a means to establish a comparable endocrine milieu for animals at necropsy. The procedure for obtaining a vaginal smear is relatively non-invasive and is one to which animals can become readily accustomed. It requires few supplies, and with some experience the assessments can be easily performed in fresh, unstained smears, or in fixed, stained ones. When incorporated as an adjunct to other endpoint measures, a determination of a female's cycling status can contribute important information about the nature of a toxicant insult to the reproductive system. In doing so, it can help to integrate the data into a more comprehensive mechanistic portrait of the effect, and in terms of risk assessment, may provide some indication of a toxicant's impact on human reproductive physiology.
authors.affiliation: Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA. goldman.jerome@epa.gov
authors.forename: Jerome M
authors.initials: JM
authors.lastname: Goldman
authors.forename: Ashley S
authors.initials: AS
authors.lastname: Murr
authors.forename: Ralph L
authors.initials: RL
authors.lastname: Cooper
mesh_terms: D000818:Animals; D030762:Estrous Cycle / Q000502:physiology*; D037901:Euthanasia, Animal / Q000379:methods; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology; D007633:Keratins / Q000378:metabolism; D008954:Models, Biological; D010053:Ovary / Q000187:drug effects / Q000502:physiology; D018570:Risk Assessment; D012377:Rodentia / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000187:drug effects; D018675:Toxicity Tests / Q000379:methods; D014116:Toxicology / Q000379:methods*; D014621:Vagina / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D014626:Vaginal Smears / Q000379:methods
chemical_list: D007633:Keratins