Studies and comparison of pterin patterns in the plasma of dogs and cats and their alteration in various neoplasias and virus infections

Physiological pterin levels were evaluated in plasma samples of healthy dogs and cats. Biopterin and 7-xanthopterin were determined quantitatively by HPLC after partial purification by ion exchange chromatography. Neopterin, pterin and 6-hydroxymethylpterin were not detectable in plasma samples. Pterin levels in plasma of dogs with neoplasias and cats with neoplasias or viral infections (FeLV, FIV, FIP) were determined. Dogs with various tumours did not show qualitative but distinct quantitative alterations in the pterin concentration in plasma. Biopterin concentrations in plasma of dogs after tumour exstirpation significantly decreased compared to the levels before surgery. There was only a moderate increase of the biopterin levels in plasma of cats with neoplasias in comparison to healthy animals of this species. Cats suffering from viral infections, however, showed a significant rise in biopterin concentrations. The results underscore the importance of pterins as sensitive indicators for the presence of activation of cell mediated immune response. With emphasis on biopterin the role of pterins as helpful parameters for the preventation and the monitoring of diseases is pointed out.