Co-expression of sulfonylurea receptors and K(ATP) channels in hamster insulinoma tumor (HIT) cells. Evidence for direct association of the receptor with the channel

L. Aguilar-Bryan, C. G. Nichols, A. S. Rajan, C. Parker, J. Bryan

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

Cell membranes isolated from hamster insulinoma (HIT T15) cells at passages 65-74 contain high and low affinity receptors for a sulfonylurea derivative, 5-[125I]iodo,2-hydroxyglyburide (K(D) values of ~7 nM and 16 μM). Between passages 75 and 85, the estimated B(max) for the high affinity receptor decreases ~10-fold from ~1.6 to 0.16 pmol/mg membrane protein. By contrast, the density of low affinity binding sites, 800-1000 pmol/mg, is unaltered. The drop in high affinity receptors is paralleled by a decrease in the density of K(ATP) channels assessed using patch-clamp and 86Rb+-efflux techniques. These results strongly support the idea that the high affinity sulfonylurea receptor is an integral part of the K(ATP) channel.

Original languageEnglish
Pages (from-to)14934-14940
Number of pages7
JournalJournal of Biological Chemistry
Volume267
Issue number21
StatePublished - 1992

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