Fig. 1

Adding isotope tracers to adult zebrafish water achieves isotopic steady-state labeling (A) Schematic of the steady-state labeling workflow for LC-MS-based metabolomics. (B) Kinetics to achieve steady-state labeling for serum glucose from WT zebrafish in tank water containing 10 mM [U-13C] glucose. Values are mean ± SEM; n = 3–4 zebrafish per time point. (C) Serum glucose levels in WT zebrafish over the course of 10 mM [U-13C] glucose labeling. Values are mean ± SEM; n = 3–4 zebrafish per time point. (D–G) Fractional labeling, relative to serum M6 glucose, of the glycolytic intermediates glucose 6-phosphate (D), pyruvate (E), alanine (F), and lactate (G) in WT serum and liver between 18 and 24 h. Data are mean ± SEM; n = 5 zebrafish per time point. (H–K) Fractional labeling, relative to serum M6 glucose, of the metabolites α-ketoglutarate (H), succinate (I), malate (J), and glutamine (K) in WT serum and liver between 18 and 24 h. Data are mean ± SEM; n = 5 zebrafish per time point. n.d., not detected; n.s., not statistically significant according to a two-tailed paired t test; G6-P, glucose 6-phosphate; Pyr, pyruvate; Ala, alanine; Lac, lactate; α-KG, α-ketoglutarate; Suc, succinate; Mal, malate; Gln, glutamine. Full labeling data are available in Data S1.