EPA Science Inventory

RELATIONSHIP BETWEEN ETHINYLESTRADIOL-MEDIATED CHANGES IN ENDOCRINE FUNCTION AND REPRODUCTION IMPAIRMENT IN JAPANESE MEDAKA (ORYZIAS LATIPES)

Citation:

TILTON, S., C. M. FORAN, AND W. H. BENSON. RELATIONSHIP BETWEEN ETHINYLESTRADIOL-MEDIATED CHANGES IN ENDOCRINE FUNCTION AND REPRODUCTION IMPAIRMENT IN JAPANESE MEDAKA (ORYZIAS LATIPES). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 24(2):352-359, (2005).

Description:

Many biochemical endpoints currently are used to describe endocrine function in fish; however, the sensitivity of these parameters as biomarkers of impaired reproduction or sexual development is not well understood. In the present study, adult Japanese medaka (Oryzias latipes) were assessed for reproductive output and endocrine function, including circulating steroid concentrations, ex vivo steroidogenesis from the gonads, aromatase activity, hepatic estrogen receptor (ER), and plasma vitellogenin (VTG) after exposure to 0, 0.2, 5,500, and 2,000 ng/L of 17 a-ethinylestradiol (EE) for 14 d. The EE altered these biochemical responses at various sites along the hypothalamus-pituitary-gonadal axis at concentrations as low as 0.2 ng/L, but it only depressed reproductive function at concentrations of 500 ng/L or greater. Offspring also had reduced ability to hatch at 500 ng/L of EE, but this concentration did not produce any other observed changes in development or sexual phenotype. The reproductive parameters correlated well with VTG, ER, and gonadosomatic index (GSI) in both sexes of adult medaka, which could be indicative of the ER-mediated mode of action for EE. Vitellogenin and ER were elevated at higher concentrations of EE in both sexes, whereas GSI was decreased. Overall, most biochemical endpoints were more sensitive than reproduction or development to exposure, indicating that reproductive function may be relatively protected.

Purpose/Objective:

To better understand parameters of impaired reproduction or sexual development in fish in order to develop biomarkers of effect

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 02/01/2005
Completion Date: 02/01/2005
Record Last Revised: 03/25/2013
Record Created: 08/08/2005
Record Released: 08/08/2005
OMB Category: Other
Record ID: 136954

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB

GULF ECOLOGY DIVISION