(A) Plasma uridine levels in male WT and FAT-ATTAC mice in a fasting/refeeding study (n = 6 per group). (B) Relative plasma uridine levels in male WT and Agpat2 KO mice in a fasting/refeeding study (n = 4 per group). (C) qPCR quantification of genes involved in pyrimidine biosynthesis in liver from male C57BL/6 mice (n = 5 per group). (D) qPCR quantification of Cad in liver, epididymal fat (eWAT), subcutaneous fat (sWAT), and brown fat (BAT) from male C57BL/6 mice (n = 5 per group). (E) Uridine contents in subcutaneous adipose tissue biopsies from metabolically healthy subjects were reduced 5 hours after breakfast (n = 6). (F to I) Male C57BL/6 mice were treated with streptozotocin (STZ) or vehicle (CTL) and monitored for plasma glucose levels and body weight up to 7 weeks. The uridine concentrations in plasma, bile, and tissues were measured from mice fasted for 24 hours (n = 5 or 6 per group). Statistical analysis was performed for each group or treatment using the fed state or CTL treatment of that group as baseline if not specified. Data were analyzed with two-tailed Student t test. *P < 0.05, **P < 0.01, ***P < 0.001. Error bars denote SEM.