Fig. 1.

Inhibitors against inositide and related signaling pathways decrease IP₇ levels. HIT-T15 cells, labeled with 10 μCi/ml [³H] myo-inositol, were incubated with respective inhibitor for 30 min. (A) Blocking IR signaling using HNMPA-(AM)₃ decreased IP₇ levels significantly (n = 6, for control; n = 3, for 75 μM; n = 4, for 100 μM). (B) Blocking PI3K by LY294002 (n = 9, for control; n = 7, for 25 μM; n = 6, for 100 μM) decreased IP₇ levels dose dependently, whereas (C) wortmannin (n = 8, for control; n = 4, for 0.5 μM; n = 3, for 10 μM), did not decrease IP₇ levels at 0.5 μM, the most commonly used concentration. At high concentration, 10 μM, wortmannin also decreased IP₇ levels. (D) PI4K inhibitor, PAO, strongly decreased IP₇ levels dose dependently (n = 5, for control; n = 5, for 1 μM; n = 3, for 20 μM). (E) CK2 inhibitor, TBB, also reduced IP₇ levels both at 5 and 10 μM (n = 5, for control; n = 3, for 5 μM; n = 4, for 10 μM). (A- E) Data are presented as Means ± SEM, ***p < 0.001, **p < 0.01 compared to controls, one-way ANOVA followed by Tukey's multiple comparison test. (F) PLC inhibitor, U73122, decreased IP₇ levels by 31% (n = 7, for control; n = 5, for 10 μM). (G) Whereas, the negative control for PLC inhibitor, U73343, decreased IP₇ levels more potently by 66% (n = 6, for control; n = 5, for 10 μM). (F and G) Data are presented as Means ± SEM, ***p < 0.001, Student's t-test.