Fig. 5. Menadione induces PTP, which causes a loss of mitochondrial staining by calcein. (A) Transmitted light image of pancreatic acinar cell. (B) Fluorescence image of the same cell loaded with calcein in the presence of CoCl₂. (C) Calcein fluorescence of the cell during exposure to menadione. (D) Calcein fluorescence during exposure to menadione following precincubation with 50 µM bongkrekic acid. (E) 100 nM antimycin A does not cause a loss of calcein fluorescence.