title: Effects of progesterone on sperm motility in fathead minnow (Pimephales promelas).
abstract: The steroid hormone progesterone (P4) is found at relatively high concentrations (∼300 ng/L) in association with concentrated animal feeding operations (CAFOs). In an effort to better understand the potential endocrine disrupting effects of P4 in male fish, computer assisted sperm analysis (CASA) was used to evaluate the effects of this steroid on sperm motility in the fathead minnow (Pimephales promelas). The rationale for focusing on sperm motility is that certain progestins have been shown to bind to surface membrane receptors on fish spermatozoa and increase sperm swimming velocity. It was hypothesized, therefore, that sperm swimming velocity might be a useful indicator of progestin exposure in fish. Adult male fathead minnows (ages 6-12 months) were exposed to environmentally relevant doses of P4, both longer-term (1 week, in vivo exposure) and short-term (minutes, in vitro exposure). Sperm were then video recorded and analyzed by CASA. When fathead minnows were continuously exposed for 1 week to low levels of progesterone in vivo there was a significant dose-dependent reduction in sperm motility. There was no effect of short-term P4 exposure on fathead minnow sperm swimming characteristics. Additional research is required to elucidate the mechanism by which progesterone alters sperm swimming in the fathead minnow. With further validation, the fathead minnow sperm motility assay may be a useful tool to rapidly screen for endocrine disrupting chemicals in the aquatic environment.
authors.affiliation: University of Wisconsin-Madison, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Murack
authors.forename: John
authors.initials: J
authors.lastname: Parrish
authors.forename: Terence P
authors.initials: TP
authors.lastname: Barry
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000633:toxicity*; D004784:Environmental Monitoring / Q000379:methods; D008297:Male; D011374:Progesterone / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects; D054712:Salinity; D012965:Sodium Chloride / Q000633:toxicity; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D052244:Endocrine Disruptors; D014874:Water Pollutants, Chemical; D012965:Sodium Chloride; D011374:Progesterone