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We have examined the metabolism of ketone bodies in neuroblastoma C1300 and glioma C6 cells, two established lines of neural origin. The three ketone body-metabolizing enzymes are present in cells of both lines in the relative proportions normally found in brain (D-3-hydroxybutyrate dehydrogenase < acetoacetyl-CoA thiolase < 3-ketoacid CoA-transferase), the activities of the first two are higher in glioma cells than in neuroblastoma, and that ofthe third is 2-fold higher in neuroblastoma cells than in glioma cells. The specific activity of 3-ketoacid CoAtransferase (EC 2.8.3.5) in both cell lines increased as the cultures achieved confluence, then decreased. Ketone bodies and especially acetoacetate are preferred substrates for synthesis of neural lipids in cells ofboth lines. The incorporation ofglucose carbon into lipids is significantly reduced in cells ofboth lines in the presence of ketone bodies. Addition of acetoacetate but not DL-3-hydroxybutyrate to the culture medium resulted in a significant increase in the activity of 3-ketoacid CoA-transferase and also in the rate of acetoacetate oxidation in neuroblastoma cells but not glioma cells. These findings indicate that specific differences exist in the capacity of these two cell lines to metabolize ketone bodies and also that substrate-level regulation of the ketone body-metabolizing pathway exists. These two lines therefore provide a potentially useful system in which the mechanisms of regulation ofthese enzymes may be examined.The importance of acetoacetate (AcAcO) and D-3-hydroxybutyrate (D-3-HB) as fuels for cerebral metabolism and as precursors for lipid synthesis in developing rat brain has been well documented (for review see refs. 1 and 2). Although the metabolism of these ketone bodies by in vivo and in vitro brain preparations has been investigated, very little is known about their metabolism by neuronal and glial cells (3)(4)(5). Because pure preparations ofglial and neuronal cells are difficult to obtain and to maintain in culture, established lines of glial and neuronal origin have been widely used as representatives of these cell types (6). Even after transformation, these clonal cell lines retain many of their characteristic metabolic pathways (7,8).The present study was, therefore, initiated to investigate possible differences in the metabolism of ketone bodies between two established clonal cell lines, namely glioma C6 and neuroblastoma C1300 (N2a). The results show that there are specific differences between these two cell lines of glial and neuronal origin with respect to their capacities to metabolize ketone bodies and in their regulation by exposure to ketone bodies. MATERIALS AND METHODSCell Culture. Rat glioma C6 and mouse neuroblastoma C1300 (N2a) clones were maintained in Eagle's minimal essential medium containing 4-fold increased concentrations ofamino acids and vitamins, and supplemented with 10% fetal calf serum, penicillin at 100 units/ml, and streptomycin at 100 pZg/ ml. The medium also contained 5 mM glucose and 2 m...

An automated radiosynthesis of carbon‐11 positron emission tomography radiotracer [11C]UCB‐J for imaging the synaptic density biomarker synaptic vesicle glycoprotein SV2A was established using Synthra RNPlus synthesizer. Commercially available trifluoroborate UCB‐J analogue was used as a radiolabelling precursor, and the desired radiolabelled product was isolated in 11 ± 2% (n = 7) nondecay corrected radiochemical yield and formulated as a 10% EtOH solution in saline with molar activities of 20 to 100 GBq/μmol. The method was based upon the palladium(0)‐mediated Suzuki cross‐coupling reaction and [11C]CH3I as a radiolabelling synthon. The isolated product was cGMP compliant as demonstrated by the results of quality control analysis.

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