1. @entity413 -induced insulin release from single islets of Langerhans is pulsatile. We have investigated the correlation between changes in cytosolic free @entity460 concentration ([ @entity141 ]i) and oscillatory insulin secretion from single @entity19 islets, in particular examining the basis for differences in secretory responses to intermediate and high @entity413 concentrations. Insulin release was monitored in real time through the amperometric detection of the surrogate insulin marker @entity750 ( @entity750 ) via @entity505 fibre microelectrodes. The [ @entity141 ]i was simultaneously recorded by whole-islet @entity593 microfluorometry. 2. In 82 % of the experiments, exposure to 11 mM @entity413 evoked regular high-frequency (average, 3.4 min-1) @entity7158 in amperometric current and [ @entity141 ]i. In the remaining experiments (18 %), 11 mM @entity413 induced an oscillatory pattern consisting of high-frequency [ @entity141 ]i oscillations that were superimposed on low-frequency (average, 0.32 min-1) [ @entity141 ]i waves. Intermittent high-frequency [ @entity141 ]i oscillations gave rise to a similar pattern of pulsatile @entity750 release. 3. Raising the @entity413 concentration from 11 to 20 mM increased the duration of the steady-state [ @entity141 ]i oscillations without increasing their amplitude. In contrast, both the duration and amplitude of the associated @entity750 transients were increased by @entity413 stimulation. The amount of @entity750 released per secretion cycle was linearly related to the duration of the underlying [ @entity141 ]i oscillations in both 11 and 20 mM @entity413 . The slopes of the straight lines were identical, indicating that there is no significant difference between the ability of @entity460 oscillations to elicit @entity750 /insulin release in 11 and 20 mM @entity413 . 4. In situ @entity750 microamperometry has the potential to resolve the high-frequency oscillatory component of the second phase of @entity413 -induced insulin secretion. This component appears to reflect primarily the duration of the underlying [ @entity141 ]i oscillations, suggesting that @entity413 metabolism and/or access to @entity413 metabolites is not rate limiting to fast pulsatile insulin release.

Control of pulsatile @entity750 /insulin secretion from single XXXX pancreatic islets by intracellular @entity460 dynamics.

@entity7158 :: ('MESH:D009378', 'Disease') :: ['synchronous oscillations'] @entity19 :: ('10090', 'Species') :: ['mouse'] @entity593 :: ('MESH:D016257', 'Chemical') :: ['fura-2'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon'] @entity750 :: ('MESH:D012701', 'Chemical') :: ['5-hydroxytryptamine', '5-HT'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca2+'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose', 'Glucose']
@entity19 :: (10090,Species) :: ['mouse']
