Figure 5. Ablation of GHS-R prevents age-associated decline of norepinephrine (NE) and enhances NE-responsiveness. NE concentrations in the urine (A) and NE levels in BAT (B) of young, middle-aged and old WT and Ghsr−/− mice. Young (4-months), middle-aged (10-months) and old (22-months) mice were used. (C) β3-AR mRNA expression in BAT of 22 month-old WT and Ghsr−/− mice. N = 6-10. *p<0.05, WT vs. Ghsr−/−; #p<0.05, ##p<0.001, old or middle-aged vs. young.