A 17β–estradiol dose-response study demonstrated differential hepatic mRNA expression between the reference Tuckerton population and the chemically impacted Newark Bay F. heteroclitus for (A) chg H, (B) chg Hm, (C) chg L, (D) vtg1 and (E) vtg2. Within both Tuckerton and Newark Bay populations, expression of all genes with all 17β–estradiol treatments was higher than respective uninjected controls. Overall, expression levels were significantly lower for all genes in E2 treatment groups for Newark Bay killifish compared to Tuckerton, except for 1000 ng E2/g (chg H) and 100 ng E2/g (chg Hm and chg L). Doses were nanograms of 17β– estradiol injected per gram body weight (parts-per-billion). *Fold-differences in mean expression between populations are shown for each treatment that was significantly differentially expressed between populations. Fold-inductions for each treatment over the population’s respective control are shown in Table 2. Data are reported as mean ± standard deviation (N = 7 per group). p ≤ 0.05 was regarded as significantly different (Two-Way ANOVA, Tukey’s post-hoc).