Effect of 6-hydroxydopamine on the metabolism of endogenous octopamines and catecholamines.
The daily excretion in rat urine of o-(OHMA) (0.2), m-(MHMA) (0.9), p-(PHMA) hydroxymandelic acid (78), vanillylmandelic acid (VMA) (3.5) and homovanillic acid (30 micrograms day-1), terminal metabolites of the isomeric octopamines and catecholamines, has been determined by gas chromatography-mass spectrometry. Chemical sympathectomy with 6-hydroxydopamine (i.p.) caused the daily output of each acid (except OHMA) to drop by 50% and that of PHMA was restored to normal the most rapidly after cessation of treatment. These results indicate that m- and p- (but not o-) octopamine coexist with catecholamines in sympathetic nerve terminals, are subject to the same compensatory biosynthetic mechanism following chemical sympathectomy and that p-octopamine has the highest turnover rate of these biogenic amines in the rat.
Ibrahim
K E
KE
Williams
C M
CM
D000818:Animals; D002395:Catecholamines / Q000378:metabolism* / Q000652:urine; D006863:Hydrogen-Ion Concentration; D006892:Hydroxydopamines / Q000494:pharmacology*; D008297:Male; D009655:Octopamine / Q000652:urine*; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains
D002395:Catecholamines; D006892:Hydroxydopamines; D009655:Octopamine; D016627:Oxidopamine