Use of r-[1-11c]-[beta]-hydroxybutyrate in pet studies of regional cerebral uptake of ketone bodies in man. Blomqvist, G., J O. Thorell, M. Ingvar, V Grill, L. Wid[acute]en, S. Stone-Elander. Depts. of Clinical Neuroscience, Karolinska Pharmacy, and Endocrinology, Karolinska Hospital, S-17176 Stockholm, Sweden
APStracts 2:0141E, 1995.
A method for determining regional cerebral utilization of ketone bodies in man is described. Following a bolus injection of R-[1-11C] -[beta]-hydroxybutyrate, the time course of the tracer in the brain was measured with positron emission tomography in five healthy volunteers. The regional cerebral blood flow was measured separately. The tracer uptake in the brain could be well described by a single rate constant, indicating that the concentration of unmetabolized ketone bodies in the brain is very low and that transport across the blood-brain barrier is the rate limiting step. At an average plasma concentration of [beta]-hydroxybutyrate of 0.043 [mu]mol ml-1, the utilization rate was estimated to be 0.48 nmol ml-1 min-1. In accordance with previous animal studies, the utilization rate was found to increase almost linearly with increasing plasma concentration of [beta]-hydroxybutyrate. Furthermore, the utilization was higher in grey than in white matter and, finally, the ratio between the utilization in the basal ganglia and the brain as a whole was lower for ketone bodies than for glucose. 

Received 28 March 1995; accepted in final form 22 June 1995.
APS Manuscript Number E146-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 11 July 1995.