Abstract
One of the major metabolites of norepinephrine in rat brain is 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MOPEG-SO4). The rate of formation in brain of MOPEG-SO4 was estimated by: 1) determining the rate of its accumulation after treatment with probenecid and 2) determining the initial rate of decline of MOPEG-SO4, after inhibition of monoamine oxidase with pargyline. The rate of formation of MOPEG-SO4, appeared to be about 20 to 35% of the rate previously reported for norepinephrine. We also observed that increasing the turnover of norepinephrine by injection of phenoxybenzamine increased the rate of formation and the concentration of MOPEG-SO4 in brain. Cold exposure, which also accelerates the rate of formation of norepinephrine in brain, increased the concentration of MOPEG-SO4 in brain. Neither treatment had an appreciable effect on the steady-state concentration of norepinephrine. Measuring MOPEG-SO4 formation by the above procedures or simply measuring the concentration of MOPEG-SO4 may be a useful technique for revealing changes in the synthesis of norepinephrine in rat brain.
Footnotes
- Received June 7, 1972.
- Accepted November 18, 1972.
- © 1973 by The Williams & Wilkins Co.
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