The ATP- and tolbutamide-sensitivity of the ATP-sensitive K-channel from human pancreatic B cells

Diabetologia. 1989 Aug;32(8):591-8. doi: 10.1007/BF00285333.

Abstract

The ATP- and sulphonylurea-sensitivity of the ATP-sensitive K-channel was measured in human pancreatic B cells. In inside-out patches, half-maximal inhibition of channel activity was produced by 10 mumol/l ATP (with 2 mM Mg2+) and ATP-inhibition was partially antagonised by ADP. A significantly lower sensitivity to ATP was found in whole-cell recordings. Tolbutamide inhibited whole-cell ATP-sensitive K-currents half-maximally at 18 mumol/l; the sensitivity to tolbutamide was somewhat less in the inside-out patch. Ca-activated K-channels were unaffected by tolbutamide (10 mmol/l). These results resemble those found for rodent B cells and suggest that sulphonylureas exert their therapeutic effects in Type 2 (non-insulin dependent) diabetes by inhibition of the ATP-sensitive K-channel.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology*
  • Calcium / pharmacology
  • Humans
  • In Vitro Techniques
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / physiology*
  • Kinetics
  • Membrane Potentials / drug effects
  • Potassium Channels / drug effects
  • Potassium Channels / physiology*
  • Tolbutamide / pharmacology*

Substances

  • Potassium Channels
  • Adenosine Triphosphate
  • Tolbutamide
  • Calcium