An insulin mediator preparation serves to stimulate the cyclic GMP activated cyclic AMP phosphodiesterase rather than other purified insulin-activated cyclic AMP phosphodiesterases

N J Pyne, M D Houslay

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An insulin mediator preparation was obtained from rat hepatocytes which had been treated with insulin. This preparation inhibited adenylate cyclase activity. It stimulated the activity of homogeneous preparations of both the cytosolic and membrane-bound forms of rat liver cyclic GMP-activated cyclic AMP phosphodiesterase. It failed to activate homogeneous preparations of both the peripheral plasma membrane and 'dense-vesicle' cyclic AMP phosphodiesterases. The insulin mediator preparation stimulated cyclic GMP-activated cyclic AMP phosphodiesterase activity in a dose-dependent fashion with a hill coefficient of 0.46. Insulin caused the dose-dependent production of mediator activity in intact hepatocytes with a Ka of 9 pM, although concentrations of insulin greater than 10 nM progressively reduced stimulatory activity.
Original languageEnglish
Pages (from-to)290-296
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - 14 Oct 1988


  • 3',5'-cyclic-AMP phosphodiesterases
  • adenylate cyclase
  • animals
  • cells, cultured
  • cyclic GMP
  • glucagon
  • insulin
  • isoenzymes
  • kinetics
  • liver
  • second messenger systems

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