The effects of estradiol on 17β-hydroxysteroid dehydrogenase type IV and androgen receptor expression in the developing zebra finch song system

► Showed that males have a higher degree of co-localization of HSD17B4 and AR in HVC than females. ► Demonstrated that developmental treatment with E2 up-regulates the expression of HSD17B4 mRNA in HVC to male-typical levels. ► This treatment does not increase the co-localization of HSD17B4 and AR in females.