Norepinephrine stimulation of pentose cycle in rat brain prisms

Using the C1/C6 ¹⁴CO₂ ratio as a relative measure of pentose shunt metabolism, rat brain prisms were incubated with (1-¹⁴C) or (6-¹⁴C) glucose and respired ¹⁴CO₂ collected. Shunt metabolism was stimulated with 10-⁴ but not 10^-5M norepinephrine. MAO inhibitors and reserpine blocked norepinephrine stimulation but uptake inhibition did not. These data demonstrate that, under the tested conditions, MAO mediated norepinephrine metabolism does stimulate shunt activity but not at physiological concentrations.