Abstract
Catecholamine (CA) and 5-hydroxytryptamine (5-HT) concentrations in the yolk, albumen, whole embryo, brain, heart, liver and kidney of embryonic and developing White Leghorn chicks were determined by high performance liquid chromatography. The brain, kidney, heart and liver were dissected from embryos after 12, 14, 16, 18 and 20 days of incubation, and 3, 7, 11, 15, 19, 39, 59, 99 and 159 days after hatching. 5-HT was found in the fertilized and unfertilized yolk, but CA was not found in either. The 5-HT concentration in the fertilized yolk increased until hatching, while it decreased in the unfertilized yolk. CA and 5-HT were found in the whole embryo on the 6th day, and their concentration increased with development.
The CA and 5-HT concentrations in the brain increased from the embryonal stage to the 15th day after hatching, and then they became stable. The CA and 5-HT concentrations fluctuated in the heart, liver and kidney. It was interesting that the 5-HT concentration in the liver and norepinephrine concentration in the kidney showed a very large peak during hatching.
