FIGURE 1.

Insulin regulates respiration in human mucosal epithelial cells. hTCEpi cells and HBECs were cultured in growth media (KGM), basal media (KBM), and KBM containing 5 μg/mL of human recombinant insulin (KBM INS) for 48 hours. A,B, OCR and ECAR measurements in hTCEpi cells and HBECs. A, In hTCEpi cells, culture in KBM reduced cellular oxygen uptake (OCR). This decrease was blocked by co-treatment with insulin. Insulin also increased the extracellular acidification rate (ECAR). B, In HBECs, OCR and ECAR both decreased in KBM and were increased with insulin. C,D, The ratio of OCR to ECAR characterizes the metabolic phenotype. C, hTCEpi cells exhibit a more glycolytic phenotype in KBM, which was further increased in the presence of insulin. D, HBECs demonstrated a more respiratory phenotype in KBM that was unchanged by insulin. E,F, ATP production per min for hTCEpi cells and HBECs. ATP levels paralleled respiration for both cell types. G-J, OCR and ECAR in hTCEpi cells (G, I) and HBECs (H, J) plotted as a function of time. Data expressed as mean ± standard deviation from one representative experiment. One-way ANOVA, Holm-Sidak multiple comparisons test. n = 5