Vivo Findings Related to 5-Hydroxytryptophan Decarboxylase

5HTP decarboxylase has been found in all tissues which contain serotonin. In the central nervous system the localization of 5HTP decarboxylase parallels the localization of serotonin (Gaddum and Giarman, 1956 Bogdanski et al., 1957). Tissues, such as cerebellum, which contain little serotonin contain but traces of 5HTP decarboxylase, whereas hypothalamus is rich in both. From these and other considerations it would appear that serotonin is made centrally. 

Serotonin Levels in Normal and Vitamin B6-depicient Chicks  

It has also been possible to show marked diminution in the serotonin depots of chicks which were raised from hatching on a vitamin Be-defi-cient diet (Weissbach et al., 1957a). As shown in Table I the amount of serotonin in all tissues was markedly diminished. When 5HTP was adminis- 

Nakai (1958) has demonstrated that in herbivores the low excretion of 5HIAA can be explained by pigment formation from the intermediate 

Using the partially purified soluble MAO which had been separated from aldehyde dehydrogenase, it was possible to obtain appreciable quantities of the intermediate, 5-hydroxyindole-3-acetaldehyde, and to determine some of its properties. Contrary to expectations this aldehyde was found to be relatively stable when kept in dilute solution. This same enzyme preparation was used to prepare the corresponding aldehyde from norepinephrine, i.e., 3,4-dihydroxyphenylglycolic aldehyde (keeper et al., 1958). It is of interest that this aldehyde was also found to be surprisingly stable in dilute aqueous solution. 

---