Protein rich diet suppressed net and unidirectional clearances of 6-[F-18]Fluoro-DOPA to striatum but did not alter relative DOPA decarboxylase activity

Journal Article · Sun May 01 04:00:00 EDT 1994 · Journal of Nuclear Medicine

OSTI ID:198070

Kuwabara, H; Cumming, P; Reutens, D ^[1]

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1. Montreal Neurological Institute, Montreal (Canada); and others

We examined the effects of competitors in plasma (i.e., large neutral amino acids, LNAA) on the transport across the blood-brain-barrier and decarboxylation of tracer FDOPA in human striatum. We studied 10 healthy, neurologically normal subjects with the Scanditronix PC 2048-15B PET camera for 2 hours following intravenous injection of FDOPA. The subjects were either fasted overnight (n=6, ages:23-42 years) or received protein rich diet ({approximately}50 g protein) 1 hour before the study (n=4, ages:21-40 years). During the study, we obtained time-courses of radioactivity in arterial plasma and separated FDOPA and O-methyl-fluoro-DOPA with HPLC. We estimated, by means of least-squares optimization, the unidirectional blood-brain D clearance (K{sub 1}{sup D}), relative DOPA decarboxylase activity (k{sub 3}{sup D}), and effective vascular volume (V{sub 0}) in striatum while the partition volume (V{sub e}=K{sub 1}/k2) was set to the individual`s estimates of frontal lobe. The net clearance (K{sup D}) was calculated as K{sub 1}{sup D}k{sub 3}{sup D}/(k{sub 2}{sup D}+k{sub 3}{sup D}).

• OSTI ID: 198070
• Report Number(s): CONF-940605--
• Journal Information: Journal of Nuclear Medicine, Journal Name: Journal of Nuclear Medicine Journal Issue: Suppl.5 Vol. 35; ISSN 0161-5505; ISSN JNMEAQ
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
AMINO ACIDS
BLOOD-BRAIN BARRIER
DECARBOXYLATION
DIET
DOPA
INTRAVENOUS INJECTION
MEMBRANE TRANSPORT
PLASMA
POSITRON COMPUTED TOMOGRAPHY
TRACER TECHNIQUES