title: DL-Threo-3,4-dihydroxyphenylserine does not exert a pressor effect in orthostatic hypotension.
abstract: DL-Threo-3,4-dihydroxyphenylserine (DL-DOPS) was given to six subjects with severe orthostatic hypotension (OH). On separate days each subject took either 600 or 800 mg DL-DOPS or placebo. DL-DOPS increased norepinephrine (NE) excretion 10,000% and urinary normetanephrine and dihydroxyphenylglycol excretion 400%. DL-DOPS, however, led to only slight increases in excretion of the major NE metabolites 3-methoxy-4-hydroxyphenylglycol and vanillylmandelic acid. Only approximately 2.2% +/- 0.5% (range 0.65% to 3.8%) of the L-stereoisomer (L-DOPS), when given as DL-DOPS, is converted to NE in vivo over 24 hr. DL-DOPS did not affect either supine or upright blood pressure in our subjects. Our findings do not support reports that DL-DOPS may be therapeutically useful in OH.
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001794:Blood Pressure / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D015103:Droxidopa / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D004341:Drug Evaluation; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic / Q000188:drug therapy*; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000652:urine; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood / Q000652:urine; D009647:Normetanephrine / Q000652:urine; D011187:Posture; D012694:Serine / Q000031:analogs & derivatives*
chemical_list: D009647:Normetanephrine; D012694:Serine; D008734:Methoxyhydroxyphenylglycol; D015103:Droxidopa; C010117:3,4-dihydroxyphenylglycol; D009638:Norepinephrine