2-amino-4-hydroxy-6-formylpteridine and 5-methoxytryptophan

The pineals of 28 days old male Wistar rats, in December periodically exposed to either white or green light, were incubated with pterin-6-aldehyde or reduced neopterin. In white light the rhythm of synthesis of 5-methoxytryptophan and of 5-methoxyindole-3-acetic acid was clearly influenced by the pteridines mentioned. In green light a change in rhythmicity of 5-methoxytryptophan, 5-methoxytryptamine and of melatonin/5-methoxytryptophol synthesis by the pteridines was observed. In white light both pteridines increased 5-methoxytryptophan and decreased 5-methoxyindole-3-acetic acid synthesis. Reduced neopterin stimulated 5-methoxytryptamine synthesis and inhibited melatonin/5-methoxytryptophol synthesis. Pterin-6-aldehyde showed an opposite effect. In green light both pteridines decreased 5-methoxytryptophan synthesis, but increased 5-methoxyindole-3-acetic acid and 5-methoxytryptamine synthesis. Melatonin/5-methoxytryptophol synthesis was decreased by reduced neopterin and increased by pterin-6-aldehyde. The results suggest an indolic metabolic pathway leading from 5-methoxytryptophan via 5-methoxytryptamine to melatonin, while pteridines and light of different wave lengths are correlated in regulating indole metabolism.

Topics: 5-Methoxytryptamine; Animals; Biopterins; Hydroxyindoleacetic Acid; Indoles; Light; Male; Melanins; Neopterin; Pineal Gland; Pteridines; Pterins; Rats; Rats, Inbred Strains; Tryptophan