2-amino-4-hydroxy-6-formylpteridine and isoxanthopterin

After iodine oxidation, biopterin, 6-hydroxymethylpterin, and 6-formylpterin were identified in mouse spleen lymphocytes by means of reverse-phase HPLC, Crithidia assay, and oxidative degradation. Concanavalin A activation induces a 30-fold increase in the pteridine amounts; biopterin as well as the sum of the carbinol and the aldehyde attain levels of 6-8 X 10(-12) mol/10(6) cells. The most rapid increase occurs during the first 24 hr. Thus, pteridine accumulation precedes the period of lymphocyte proliferation; maximum DNA synthesis was found after 72 hr. Biopterin remains largely inside the cells, whereas 6-hydroxymethylpterin and 6-formylpterin were found in the supernatant if the stimulated cells were subsequently incubated in a phosphate buffered salt solution (PBS). Isoxanthopterin was found in the PBS supernatant of control cells that previously were kept in medium alone rather than subjected to lectin stimulation. Only minimal amounts were found inside these cells, and this pterin was absent from the stimulated lymphocytes. The early increase in cellular pteridines and their differential release may well provide the basis for their modulating effect on interleukin-2 activity (Ziegler I, et al: Lymphokine Research 3:284, 1984).

Topics: Animals; Biopterins; Concanavalin A; In Vitro Techniques; Kinetics; Lymphocyte Activation; Lymphocytes; Male; Mice; Mice, Inbred Strains; Pteridines; Pterins; Spleen; Xanthopterin

The influence of three pterin derivatives on the diurnal fluctuations of HIOMT (hydroxyindole-O-methyl transferase) activity was studied in the isolated pineal glands of 42-day old male Wistar rats during the month of October. The method used permitted the separate determination of four HIOMT activities. --Reduced neopterin stimulated the methylation of the substances, 5-HTP, 5-HT and 5-HIAA (see abbreviations in Material and methods), during the night. HIOMT action on the combinations N-Ac-5-HT/5-HTL was shifted to a later moment in the dark period. --Pterin-6-aldehyde stimulated HIOMT action on 5-HT during the daytime. HIOMT action on the substrates 5-HTP, 5-HIAA and N-Ac-5-HT/5-HTL was shifted towards an earlier period. --Isoxanthopterin did not exert any influence on diurnal variation in the four HIOMT activities. It may be concluded that reduced neopterin and pterin-6-aldehyde influenced the activity and the circadian rhythmicity of 5-methoxyindole synthesis. Those alterations might be important in the regulation of reproduction.

Topics: 5-Hydroxytryptophan; Acetylserotonin O-Methyltransferase; Animals; Biopterins; Circadian Rhythm; Hydroxyindoleacetic Acid; Hydroxytryptophol; Male; Methylation; Methyltransferases; Neopterin; Pteridines; Pterins; Rats; Rats, Inbred Strains; Serotonin; Xanthopterin