TY - JOUR T1 - THE RATE OF FORMATION OF 3-METHOXY-4-HYDROXYPHENYLETHYLENEGLYCOL SULFATE IN BRAIN AS AN ESTIMATE OF THE RATE OF FORMATION OF NOREPINEPHRINE JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 570 LP - 575 VL - 184 IS - 3 AU - J. L. MEEK AU - N. H. NEFF Y1 - 1973/03/01 UR - http://jpet.aspetjournals.org/content/184/3/570.abstract N2 - 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. © 1973 by The Williams & Wilkins Co. ER -