(A) Relative mRNA levels of AHR-related genes in gastrocnemius muscle specimens from non-PAD adults (n=15) and PAD patients with (n=10) and without CKD (n=8). (B) Relative expression of Ahr and Cyp1a1 in the gastrocnemius muscle of mice with and without CKD in both control and ischemic limbs (n=5/group). (C) Quantified levels of tryptophan-derived AHR ligands in the serum of mice with and without CKD (n=8 male Con, 4 female Con, 8 male CKD, 8 female CKD). (D) qPCR analysis of relative mRNA levels of Cyp1a1 following acute treatment with AHR ligands in both murine (n= 10 DMSO, 8 indoxyl sulfate, 9 L-kynurenine, and 10 kynurenic acid) and human cultured myotubes (n=10 DMSO, 9 indoxyl sulfate, 10 L-kynurenine, and 10 kynurenic acid). Panels A and D were analyzed using a one-way ANOVA with Sidak’s post hoc testing. Panels B and C were analyzed using Mann-Whitney tests. *P<0.05, Error bars represent the standard deviation.