Tryptophan metabolism during the mid-period of embryonic development (chick)

Abstract

While studying the catecholamine derivatives in the allantoic fluid of the chick embryo by gas-chromatographic techniques, numerous large peaks were seen; two of the more prominent were identified as kynurenic and xanthurenic acids. When the allantoic fluid was examined at daily intervals, it was seen that the concentration of kynuneric and xanthurenic acids reached extraordinarily high values between 7 and 9 days and then underwent a 40-fold reduction at 10 days. An increase in the concentration of anthranilic acid occurred between 9 and 10 days. There was an increase in the concentration of 5-hydroxytryptamine in the allantoic fluid after 10 days, and the assayable levels of liver kynureninase increased significantly between 8 and 9 and 9 and 10 days. Additional studies included the measurement of pyridoxine derivatives in the allantoic fluid, as well as the concentration of nicotinamide-adenine dinucleotide in the liver. The qualitative changes in tryptophan metabolites between 9 and 10 days coincided temporally with an increased concentration of pyridoxal in the allantoic fluid; and an association seemed to exist between the high concentration of oxidative derivatives in the allantoic fluid at 9 days and a relatively large concentration of nicotinamide-adenine dinucleotide present in the liver at that time.