Kathleen M. Jensen

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Due to the time and expense associated with full life-cycle testing, most current toxicity tests with fish do not explicitly consider reproductive output as an endpoint but, rather, focus on early life-stage survival and development. However, some classes of chemicals could adversely impact reproduction at concentrations below those that affect development.(More)
Trenbolone acetate is a synthetic steroid that is extensively used in the United States as a growth promoter in beef cattle. The acetate is administered to livestock via slow-release implants; some is converted by the animal to 17-beta-trenbolone, a relatively potent androgen receptor agonist in mammalian systems. Recent studies indicate that excreted(More)
Cytochrome P450 aromatase (CYP19) is a key enzyme in vertebrate steroidogenesis, catalyzing the conversion of C19 androgens to C18 estrogens such as beta-estradiol (E2). The objective of this study was to assess effects of the CYP19 inhibitor fadrozole on fathead minnow (Pimephales promelas) reproductive endocrinology and physiology in a short-term(More)
A short-term reproduction assay with the fathead minnow (Pimephales promelas) has been developed to detect chemicals with the potential to disrupt reproductive endocrine function controlled by estrogen- and androgen-mediated pathways. The objective of this study was to use the assay to characterize responses of fathead minnow reproductive endocrinology and(More)
The fathead minnow (Pimephales promelas) has been proposed as a model species for assessing the adverse effects of endocrine-disrupting chemicals (EDCs) on reproduction and development. The purpose of these studies was to develop baseline reproductive biology and endocrinology data for this species to support interpretation of tests with potential EDCs.(More)
Perfluorooctanesulfonate (PFOS) is a widespread environmental contaminant emanating from the production and/or metabolism of fluorinated chemicals with a variety of applications. The goal of this work was to assess the toxicity and bioconcentration of PFOS in the fathead minnow (Pimephales promelas). Sexually mature fish were exposed via the water for 21 d(More)
Many chemicals that adversely affect reproduction and/or development do so through multiple pathways within the reproductive tract and hypothalamic-pituitary-gonadal axis. Notable in this regard are fungicides, such as prochloraz or fenarimol, which in mammals have the potential to impact endocrine function through inhibition of CYP enzymes involved in(More)
Trenbolone acetate is a growth promoter widely used for beef production in the U.S. Two biologically active metabolites of the acetate, 17beta- and 17alpha-trenbolone, are ligands of vertebrate androgen receptors and comparatively stable in the waste of treated animals. Both have been detected in surface water associated with beef feedlots, suggesting a(More)
BACKGROUND Several chemicals in the environment have the potential to inhibit aromatase, an enzyme critical to estrogen synthesis. OBJECTIVES The objective of this study was to provide a detailed characterization of molecular and biochemical responses of female fathead minnows to a model aromatase inhibitor, fadrozole (FAD). METHODS Fish were exposed(More)
Exposure of adult fathead minnows (Pimephales promelas) to the androgen 17alpha-methyltestosterone (MT) produces both androgenic and estrogenic effects, manifested as nuptial tubercle formation in females, and vitellogenin production in males and females, respectively. The present study was conducted to determine if the unanticipated estrogenic effects are(More)