Effects of glucose, chloromercuribenzene-p-sulphonic acid and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid on phosphate efflux from pancreatic islets.
Collagenase-isolated pancreatic islets of non-inbred ob/ob mice, containing more than 90% beta-cells, were labelled with radioactive orthophosphate (32P or 33P) and then subjected to non-recirculating perifusion. The basal D-glucose concentration in the perifusion medium was 2.8 mM. When the concentration was suddenly raised to 5.6, 8.3 or 16.7 mM, D-glucose promptly elicited a transient and dose-dependent release of radiophosphate. In the presence of 2.8 mM D-glucose, 0.1 mM of the poorly permeating sulphydryl blocker, chloromercuribenzene-p-sulphonic acid, also evoked a phosphate flush resembling the one induced by D-glucose. The basal radiophosphate release was partially inhibited by 1 mM 4-acetamido-4-'-isothiocyanostilbene-2,2'-disulphonic acid. However, the phosphate flush induced by 16.7 mM D-glucose was not noticeably inhibited by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid. It is concluded that the phosphate flush emanates from beta-cells and that membrane sulphydryl groups may participate in its regulation. Although at least the basal phosphate release may in part represent transmembrane transport through 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid-sensitive anion channels, other mechanisms are also likely to participate in the glucose-induced phosphate flush.
D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000494:pharmacology*; D002731:4-Chloromercuribenzenesulfonate / Q000494:pharmacology*; D000818:Animals; D005947:Glucose / Q000494:pharmacology*; D007473:Ion Channels / Q000187:drug effects*; D007515:Islets of Langerhans / Q000378:metabolism*; D051379:Mice; D010663:Phenylmercury Compounds / Q000494:pharmacology*; D010710:Phosphates / Q000378:metabolism*; D010761:Phosphorus Radioisotopes; D013267:Stilbenes / Q000494:pharmacology*
D007473:Ion Channels; D010663:Phenylmercury Compounds; D010710:Phosphates; D010761:Phosphorus Radioisotopes; D013267:Stilbenes; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D002731:4-Chloromercuribenzenesulfonate; D005947:Glucose