Results of biochemical assays for HSD17B4 activity in male and female brain regions from two experiments. (A) Comparison of HSD17B4 activity in whole telencephalon and diencephalon shows no significant differences between sex, brain region, or the interaction of sex by brain region. There is a subtle trend in the male towards higher activity in the telencephalon compared to male diencephalon and both female regions. (B) Comparison of HSD17B4 activity in two sub-regions of the telencephalon and the diencephalon showed no overall sex differences but a significant sex by brain area interaction (p = 0.017). (C) HSD17B4 activity levels measured in testes and ovaries are significantly higher than those in the brain (p < 0.001) but do not show a significant sex difference (p = 0.062). Error bars are ± s.e.m.