The present study investigated the role of adenosine in the stimulatory action of
paeoniflorin on in vitro glucose transport. Paeoniflorin increased the uptake of a radiolabeled, non-metabolizable
glucose derivative into isolated white adipocytes of Wistar rat in a concentration-dependent
manner and this action was abolished by the antagonist, 8-cyclopentyltheophylline,
at concentrations sufficient to block the adenosine A1 receptor. However, paeoniflorin failed to displace the binding of [3
H]-8-cyclopentyl-1,3-dipropylxanthine in the isolated cerebrocortex of Wistar rat.
Direct activation of the adenosine A1 receptor does not seem to be responsible for the action of paeoniflorin. The stimulatory
effect of paeoniflorin on radioactive glucose uptake was abolished in isolated rat
white adipocytes pre-incubated with the adenosine deaminase at concentrations sufficient
to metabolize endogenous adenosine. Mediation of endogenous adenosine in the action
of paeoniflorin was further supported by the assay of adenosine released into the
medium from rat white adipocytes incubated with paeoniflorin. These findings suggest
that paeoniflorin could induce the release of adenosine from isolated rat white adipocytes
and the released adenosine may activate the adenosine A1 receptor to enhance glucose uptake.
Paeoniflorin -
Paeonia lactiflora
- Ranunculaceae - adenosine A1 receptor - adipocytes - 8-cyclopentyltheophylline, [3
H]-8-cyclopentyl-1,3-dipropylxanthine - adenosine deaminase - adenosine