PLEIOTROPIC EFFECTS OF ONE-LOCUS (PP) AND 2-LOCUS (AAPP) FUR COLOR MUTATIONS ON SEROTONIN METABOLISM IN THE MINK BRAIN

Specific features of serotonin (5-hydroxytryptamine, 5-HT) metabolism were studied in the brain of mutant sapphire minks, homozygous at gene s determining silver-blue and Aleutian fur color (ppaa), and silver-bl ue minks (pp) in comparison with the standard-colored minks (++/++). I n the midbrain of sapphire mutants, the activities of tryptophan hydro xylase (TPH) and monoamine oxidase (MAO), key enzymes of 5-HT biosynth esis and catabolism, were significantly higher; an increase in the 5-H T level was statistically nonsignificant due to considerable variation in this parameter; and the level of 5-hydroxyindole-3-acetic acid rem ained unchanged. A similar increase in TPH and MAO activities was also found in the midbrain of silver-blue pp minks, suggesting that activa tion of key enzymes of 5-HT metabolism in sapphire aapp minks is assoc iated with the mutant alleles pp.