Tissue explant coculture model of the hypothalamic–pituitary–gonadal–liver axis of the fathead minnow (Pimephales promelas) as a predictive tool for endocrine disruption

Abstract

Endocrine-disrupting compounds (EDCs) can impact the reproductive system by interfering with the hypothalamic-pituitary-gonadal (HPG) axis. Although in vitro testing methods have been developed to screen chemicals for endocrine disruption, extrapolation of in vitro responses to in vivo action shows inconsistent accuracy. The authors describe a tissue coculture of the fathead minnow (Pimephales promelas) HPG axis and liver (HPG-L) as a tissue explant model that mimics in vivo results. Brain (hypothalamus), pituitary, gonad, and liver tissue explants from adult fish were examined for function both individually and in coculture to determine combinations and conditions that could replicate in vivo behavior. Only cocultures had the ability to respond to an EDC, trenbolone, similarly to in vivo studies, based on estradiol, testosterone, and vitellogenin production trends, where lower exposure doses suppressed hormone production but higher doses increased production, resulting in distinctive U-shaped curves. These data suggest that a coculture system with all components of the HPG-L axis can be used as a link between in vitro and in vivo studies to predict endocrine system disruption in whole organisms. This tissue-based HPG-L system acts as a flexible deconstructed version of the in vivo system for better control and examination of the minute changes in system operation and response on EDC exposure with options to isolate, interrogate, and recombine desired components. Environ Toxicol Chem 2016;35:2530-2541. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.

Effects of GnRH and the dual regulatory actions of GnIH in the pituitary explants and brain slices of Astyanax altiparanae males

“…Therefore, we decided to use a medium-term exposure (12 h) to evaluate the acute effects (< 24 h) of cGnRH2 and zGnIH-3 in pituitaries and brain slices from A. altiparanae males. For the brain slices, we did not perform any standardization experiment, however previous studies in fathead minnow (Pimephales promelas) have standardized these culture conditions, showing high tissue viability until 48 h of culture (Johnston et al, 2016).…”

Research Progress of Zebrafish Model in Aquatic Ecotoxicology

“…Since the vitellogenin gene is a more sensitive biomarker than the vitellogenin protein, detection of the expression of the vitellogenin gene Vtg1 in the liver of male fish is a common method to evaluate the estrogen effect of endocrine disruptors in the environment [80]. In addition, the reproductive ability of fish is generally regulated by the hypothalamic-pituitary-gonadal axis (HPG axis) and the liver, and gamete development and oocyte maturation are regulated using estradiol and testosterone [81]. The HPG axis is a novel analytical model that has been used to study the ecotoxicogenomics of endocrine disruptors and the effects of steroid hormone synthesis genes on the fertility of gonadal tissues [82].…”

A comparative study of 3 alternative avian toxicity testing methods: Effects on hepatic gene expression in the chicken embryo

“…Liver slice culture. Liver slices were prepared from 4, day 19 chicken embryos based on methods described previously (Lorenzen et al 2001;Johnston et al 2016), with modifications for chicken embryonic liver as follows. Embryos were dissected, one at a time.…”