Sulfate Conjugates of Catecholamines in the Allantoic Fluid of the Chicken Embryo

In addition to free dopamine (DA), norepinephrine (NE), and epinephrine (E), the allantoic fluid of the 13-day-old chicken embryo contains sulfate conjugates of these three catecholamines (CAs). The concentration of DA sulfate is relatively low, while NE and E sulfates occur at levels similar to those of the free fractions. The comparatively low concentration of free CAs in the amniotic fluid, seen in a previous study, is confirmed. However, the amniotic barrier for sulfated CAs is much stronger, possibly absolute. Though some technical difficulties remain to be resolved, the chicken embryo may become a useful model for the study of the prenatal functions of CA conjugates.