Although the research described in this article has been funded wholly or in part by the U.S. Environmental Protection Agency, it has not been subjected to the Agency's required peer and policy review and therefore does not necessarily reflect the views of the Agency, and no official endorsement should be inferred. This is publication 106 of the National Oceanic and Atmospheric Administration's Center for Sponsored Coastal Ocean Research NGOMEX06 program.
Testing and applying a fish vitellogenesis model to evaluate laboratory and field biomarkers of endocrine disruption in Atlantic croaker (Micropogonias undulatus) exposed to hypoxia†
Article first published online: 9 DEC 2009
Copyright © 2009 SETAC
Environmental Toxicology and Chemistry
Volume 28, Issue 6, pages 1288–1303, June 2009
How to Cite
Murphy, C. A., Rose, K. A., Rahman, M. S. and Thomas, P. (2009), Testing and applying a fish vitellogenesis model to evaluate laboratory and field biomarkers of endocrine disruption in Atlantic croaker (Micropogonias undulatus) exposed to hypoxia. Environmental Toxicology and Chemistry, 28: 1288–1303. doi: 10.1897/08-304.1
- Issue published online: 9 DEC 2009
- Article first published online: 9 DEC 2009
- Manuscript Accepted: 22 DEC 2008
- Manuscript Received: 1 JUL 2008
- Atlantic croaker;
- Simulation model;
Recently, hypoxia has been shown to act as an endocrine disruptor. We used a model of vitellogenesis in a female sciaenid fish to simulate the effects of hypoxia and to determine if reproductive impairment observed in field-caught fish could be attributed to dissolved oxygen conditions at the sampling sites. The model is a set of coupled, ordinary differential equations that simulate major biochemical reactions from the secretion of gonadotropin to production of vitellogenin. Various intermediate variables in the model correspond to commonly measured biomarkers, and we assume a direct relationship between cumulative vitellogenin (VTG) and the gonadosomatic index (GSI). Model predictions were compared to results of laboratory studies that examined the effects of hypoxia on Atlantic croaker (Micropogonias undulatus) reproduction. When hypoxia was assumed to cause reduced gonadotropin and impaired aromatase activity, model predictions of VTG production were similar to laboratory-measured reductions in GSI. The model was then applied to reproductive biomarkers measured in fish from normoxic and hypoxic locations in Pensacola Bay (FL, USA). We simulated the relationship between reduced estradiol-17β and VTG production under hypoxia, and we compared these results with field data. Good agreement between field and simulation results suggested that croaker collected from hypoxic sites in October were exposed to hypoxic conditions for an extended period during gonadal recrudescence and that hypoxia was a dominant cause for the reduced GSIs. Monte Carlo uncertainty analyses suggested that the maximum rate of free testosterone production is the most sensitive parameter. Our simulations demonstrated that the model can be used identifying the mechanism underlying endocrine disruption and for interpreting field-measured biomarkers in situations of multiple stressors.