Fig. 4. Acute sleep loss induces tissue-specific changes in clock genes and downstream pathways in healthy young men.

Representative blots for protein abundance of BMAL1 in (A) skeletal muscle (VLM; P = 0.017; showing 8 representative pairs out of a total of 13 analyzed pairs) and in (B) SAT (P = 0.51; 6 representative pairs out of 11 analyzed pairs shown), (C) with quantification, after a night of sleep (s) and a night of sleep loss (wake or w). Western blots were normalized to loading control (see fig. S4, B and C; expression shown relative to controls that were set to 1). (D) Transcriptomic changes in core circadian clock genes, with log₂ fold change for each of the investigated tissues (VLM and SAT, n = 15 pairs for each tissue), after sleep loss (wake) compared with after normal sleep (all FDR > 0.05). (E and F) Relative gene expression of targeted genes based on qPCR (PDK4: P = 0.007; all other P > 0.10, n = 15 pairs for each tissue). BMAL1, brain and muscle Arnt-like protein-1; GLUT4, glucose transporter 4; PDK4, pyruvate dehydrogenase kinase isozyme 4; PPARD/PPARG, peroxisome proliferator–activated receptor delta (PPARD)/gamma (PPARG); s, sleep; w, wake (sleep loss). *P < 0.05 and **P < 0.05; two-sided t tests.