Effects of oral and intravenous administrations of dopamine and L-dopa on plasma levels of two isomers of dopamine sulfate in man.
The levels of two isomers of dopamine sulfate, dopamine-3-O-sulfate (DA3S) and dopamine-4-O-sulfate (DA4S), in human plasma were measured by HPLC-fluorometry. The basal plasma levels of DA3S and DA4S in the early morning were 13.8 +/- 1.9 and 3.2 +/- 0.5 pmoles/ml, respectively (means +/- S.E.M.). Oral administrations of dopamine (50 mg/body) and 1-dihydroxyphenylalanine (L-DOPA, 250 mg/body) increased the plasma levels of these dopamine sulfates almost 100-fold to 1807 +/- 266 and 1674 +/- 195 pmoles/ml of DA3S, and 466 +/- 83 and 321 +/- 76 pmoles/ml of DA4S. Intravenous dopamine infusion (5 micrograms/kg/min for 30 min) markedly increased the plasma free dopamine concentration, as expected, but increased the levels of DA3S and DA4S only slightly to 110 +/- 32 and 25 +/- 9 pmoles/ml, respectively. In contrast, intravenous L-DOPA (25 mg/body) resulted in a slight increase of free dopamine followed by marked increases of DA3S and DA4S to 691 +/- 219 and 139 +/- 40 pmoles/ml, respectively. These data indicate that O-sulfation of dopamine, especially 3-O-sulfation, is the main pathway for metabolism of intravenously and orally administered L-DOPA and orally ingested dopamine. This sulfation is suggested to occur in the gut wall.
Department of Medicine & Geriatrics, Osaka University Medical School, Japan.
K
K
Hashizume
A
A
Yamatodani
T
T
Yamamoto
T
T
Ogihara
Y
Y
Kumahara
H
H
Wada
D000284:Administration, Oral; D000328:Adult; D002851:Chromatography, High Pressure Liquid; D004298:Dopamine / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005470:Fluorometry; D006801:Humans; D007275:Injections, Intravenous; D007536:Isomerism; D007980:Levodopa / Q000494:pharmacology*; D008297:Male
C022807:dopamine 4-O-sulfate; D007980:Levodopa; C007558:dopamine 3-O-sulfate; D004298:Dopamine