Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11025652 | Toxicology in Vitro | 2019 | 7 Pages |
Abstract
Oocyte maturation can be a target of endocrine disruption by environmental chemicals capable of acting as hormone mimics, receptor blockers, and/or enzyme inhibitors. Six environmental chemicals (genistein, endosulfan, malathion, iprodione, carbaryl, and glyphosate) were selected to determine their ability to interfere with oocyte maturation in zebrafish. The translucent oocytes undergoing germinal vesicle (nucleus) breakdown (GVBD) were counted and expressed as a ratio of oocytes undergoing GVBD and total oocytes exposed. The GVBD increased significantly in oocytes exposed to 10â¯IU/ml to 100â¯IU/ml human chorionic gonadotropin (hCG). The lowest effective concentration of genistein that inhibited hCG-induced GVBD was 30â¯Î¼M, while endosulfan inhibited it at 0.03â¯Î¼M concentration. In addition, malathion inhibited hCG-induced GVBD at the lowest concentration of 60â¯Î¼M. These inhibitory effects were likely due to the chemicals acting as estrogen mimics, induction of estrogen receptors, or increase in aromatase activity resulting in enhanced estrogen action. Fungicide iprodione, possibly acting as a progestin mimic, promoted hCG-induced GVBD at the lowest concentration of 20â¯Î¼M, while the weed killer glyphosate inhibited hCG-induced GVBD starting at the 50â¯Î¼M concentration. These results demonstrate the feasibility of using fully grown zebrafish oocytes arrested at the prophase I stage in an in vitro incubation system to evaluate the effects of a variety of environmental chemicals on oocyte maturation.
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Authors
Era Maskey, Hannah Crotty, Taelah Wooten, Izhar A. Khan,