Figure 2.

Complementary measures of the effects of hIAPP on cultured cells. A, B) Dose-dependent loss of mitochondrial (MTT, red) or cytosolic reductase (CTB, blue) activity. INS-1 (A) and COS-1 (B) cells were treated with the indicated concentrations of hIAPP. Change in reductase activity is expressed as a percentage of control using protein-free carrier. For comparison, inhibition of mitochondrial and cytosolic reductase activity is also presented for 5 μM melittin. C, D) Time-dependent loss of reductase activity on incubation of INS-1 (C, solid bars) and COS-1 (D, solid bars) cells with 10 μM hIAPP (C, open bars). Reductase activity was measured 48 h after culture medium was exchanged with hIAPP-free medium. Gray bars show direct measure of viability/toxicity performed by manual counting of live, adherent cells (C) or release of cytosolic LDH to the culture medium (D).