Fig. 1

Extracellular metabolite fluctuations throughout early stages of lung branching. a Representative examples of embryonic chicken lungs at DO (0 h) (b1, b2, b3) and D2 (48 h) (B1, B2, B3) of explant culture, and corresponding in situ hybridization for l-cam, (n = 5/stage). l-cam is an epithelial marker, showing active branching formation. Scale bar: 500 µm. b Schematic representation of the glucose catabolism pathway and the potential pyruvate destinations. Blue labeling indicates the metabolites that were detected and quantified in the ¹H-NMR spectroscopy analysis. c Glucose consumption, d Alanine production, e Lactate production, and f Acetate production, during 48 h of explant culture. The medium was refreshed at D1 (24 h). Medium samples were collected at D1 (24 h) and D2 (48 h). D0 media samples were used as control. Metabolite consumption or production was calculated following the mathematical formula | (D1-D0) + (D2-D0) |. Metabolite data was normalized to the total amount of protein. Results are expressed as | mean |± SEM (n ≥ 5/stage). One-Way ANOVA and Fisher’s LSD test were performed. Significantly different results are indicated as: *p < 0.05; **p < 0.01