Trypan Blue as a marker of plasma membrane permeability in alloxan-treated mouse islet cells
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Suspensions of pancreatic islet cells from noninbred ob/ob-mice were incubated with Trypan Blue. Microscope photometry showed that apparently viable cells excluded the dye completely, whereas the nuclei of nonviable cells accumulated Trypan Blue by a saturable process. The nucleus-to-medium dye gradient was more then 30∶1 in media containing 0.1% or less Trypan Blue. The apparent affinity constant for nuclear binding of the dye was 3.1 × 104 l/mol. Albumin partially inhibited the nuclear staining. More than 0.5% Trypan Blue in the medium was toxic per se. In the absence of albumin, 0.5 or 20 mmol/l alloxan, 1 mmol/l N-ethylmaleimide, or 0.1 mmol/l chloromercuribenzene- p-sulphonic acid, but not 20 mmol/l streptozotocin, increased the frequency of islet cells stained with 0.1% Trypan Blue. The absorbance of nuclei was also increased in cells treated with alloxan or N-ethylmaleimide, but not in those treated with chloromercuribenzene- p-sulphonic acid. It is concluded that alloxan rapidly increases the permeability of the plasma membrane in mouse β-cells. This action of alloxan appears to be more acute than any such effect of streptozotocin.
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Number of pages||7|
|Journal||Journal of Endocrinological Investigation: Official Journal of the Italian Society of Endocrinology|
|Publication status||Published - 1979 Jan 1|