FIGURE 8.

Gene expression of KP enzymes in Drosophila in response to 1 month treatment with either 3‐HK, α‐MT, NAM, or α‐MT + NAM. Fold change analysis of genes in the kynurenine pathway and NAD⁺ biosynthetic pathway (n = 7–10 per treatment group). Vermilion (tryptophan 2,3‐dioxygenase) catalyzes the conversion of L‐tryptophan to N‐formyl‐L‐kynurenine. Tryptophan hydroxylase catalyzes the hydroxylation of tryptophan which is the initial and rate‐limiting step in the synthesis of the neurotransmitter serotonin. Naprt catalyzes the conversion of nicotinic acid to nicotinic acid mononucleotide. Data were analyzed using one‐way ANOVA with Tukey's multiple comparisons test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.