Norepinephrine (
noradrenaline) is a
chemical that acts as both a
hormone and as a
neurotransmitter (a substance which transmits
nerve signals from
neuron to
neuron). It is produced and secreted by the
adrenal glands.
As a hormone, it stimulates the storage or mobilization of sugar by acting on muscle and liver cells.
From the science dictionary at http://biotech.icmb.utexas.edu/