Correlation between changes in systemic D-BHB concentrations and inhibition of mast cell degranulation. Serum D-BHB concentration (Left), Intraperitoneal D-BHB concentration (Middle) and Inhibition of mast cell degranulation (Right). Fasting (Upper), Ketogenic diet (Middle) and Subcutaneous D-BHB instillation (Lower). Values are means ± SEM, n = 4 rats. CD: control diet. KD: ketogenic diet. *P < 0.05, **P < 0.01, ***P < 0.005 significantly different from initial values.