title: Trypan Blue as a marker of plasma membrane permeability in alloxan-treated mouse islet cells.
abstract: 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 X 10(4)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 nuceli was also increased in cells treated with alloxan or N-ethylmaleimide, but not in those treated with chloromercuribenze-p-sulphonic acid. It is concluded that alloxan rapidly increases the permeability of the plasma membrane in mouse beta-cells. This action of alloxan appears to be more acute than any such effect of streptozotocin.
mesh_terms: D002731:4-Chloromercuribenzenesulfonate / Q000494:pharmacology; D000496:Alloxan / Q000494:pharmacology*; D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D005033:Ethylmaleimide / Q000494:pharmacology; D066298:In Vitro Techniques; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051379:Mice; D008820:Mice, Obese; D013311:Streptozocin / Q000494:pharmacology; D014343:Trypan Blue
chemical_list: D013311:Streptozocin; D002731:4-Chloromercuribenzenesulfonate; D000496:Alloxan; D014343:Trypan Blue; D005033:Ethylmaleimide