Fig. 3

Biguanide inhibition of rotenone-sensitive respiration in permeabilized cells and isolated mitochondria. a MDBK permeabilized cells treated with biguanides at IC₅₀/5 for 30 min before ADP was added to stimulate the rates. Data show means ± standard deviation (SD) (n = 16 for control, n = 5 for proguanil and compound 2, n = 6 for compound 3, n = 7 for compound 1, and n = 8 for phenformin and compounds 4 and 5). b ADP-stimulated rotenone-sensitive oxygen consumption rates (OCRs) in permeabilized cells (% of the control, error bars show SD values). For permeabilized 143B cells: n = 10 for control, compounds 1, 2, and 4; n = 11 for phenformin and compound 3; n = 8 for compound 5; and n = 9 for proguanil. Black, data taken from Fig. 3a; gray, equivalent data from permeabilized 143B cells but using biguanide concentrations equal to IC₅₀. c Mouse heart mitochondria respiring on glutamate and malate were exposed to biguanides for 15 min before ADP was added to stimulate the rates. Biguanides concentrations were set to IC₅₀/5 (using the IC₅₀ values for mouse heart mitochondrial membranes): 0.16 mM phenformin, 0.094 mM compound 1, 0.17 mM compound 2, 0.63 mM compound 3, 6 mM compound 4, 0.058 mM compound 5, and 0.002 mM proguanil. Data show means ± standard error of the mean (SEM) (n = 8 for all compounds and n = 12 for control). d Inhibition of the ADP-stimulated rotenone-sensitive OCR in mitochondria (% of the control; mean ± SEM. For mouse liver mitochondria: n = 5 for control; n = 3 for compounds 1, 2, and 4; and n = 4 for all other compounds. For rat liver: n = 5 for control, n = 3 for proguanil and compound 5, and n = 4 for all other compounds. Black, data taken from Fig. 3c; gray, rat liver mitochondria; white, mouse liver mitochondria. For panels b and d, ****p ≤ 0.0001, ***p ≤ 0.001, **p ≤ 0.01, *p ≤ 0.05. Individual data points for panels b and d are provided in Additional file 1. con. control, phenf. phenformin, prog. proguanil, rot. rotenone