TY - JOUR
T1 - Specific activity of brain palmitoyl-CoA pool provides rates of incorporation of palmitate in brain phospholipids in awake rats
AU - Grange, Eric
AU - Deutsch, Joseph
AU - Smith, Quentin R.
AU - Chang, Michael
AU - Rapoport, Stanley I.
AU - Purdon, A. David
PY - 1995/11
Y1 - 1995/11
N2 - In vivo rates of palmitate incorporation into brain phospholipids were measured in awake rats following programmed intravenous infusion of unesterified [9,10-3H]palmitate to maintain constant plasma specific activity. Animals were killed after 2-10 min of infusion by microwave irradiation and analyzed for tracer distribution in brain phospholipid and phospholipid precursor, i.e., brain unesterified palmitate and palmitoyI- CoA, pools. [9,10-3H]Palmitate incorporation into brain phospholipids was linear with time and rapid, with >50% of brain tracer in choline-containing glycerophospholipids at 2 min of infusion. However, tracer specific activity in brain phospholipid precursor pools was low and averaged only 1.6-1.8% of plasma unesterified palmitate specific activity. Correction for brain palmitoyI-CoA specific activity increased the calculated rate of palmitate incorporation into brain phospholipids (0.52 nmol/s/g) by ~60-fold. The results suggest that palmitate incorporation and turnover in brain phospholipids are far more rapid than generally assumed and that this rapid turnover dilutes tracer specific activity in brain palmitoyl-CoA pool owing to release and recycling of unlabeled fatty acid from phospholipid breakdown.
AB - In vivo rates of palmitate incorporation into brain phospholipids were measured in awake rats following programmed intravenous infusion of unesterified [9,10-3H]palmitate to maintain constant plasma specific activity. Animals were killed after 2-10 min of infusion by microwave irradiation and analyzed for tracer distribution in brain phospholipid and phospholipid precursor, i.e., brain unesterified palmitate and palmitoyI- CoA, pools. [9,10-3H]Palmitate incorporation into brain phospholipids was linear with time and rapid, with >50% of brain tracer in choline-containing glycerophospholipids at 2 min of infusion. However, tracer specific activity in brain phospholipid precursor pools was low and averaged only 1.6-1.8% of plasma unesterified palmitate specific activity. Correction for brain palmitoyI-CoA specific activity increased the calculated rate of palmitate incorporation into brain phospholipids (0.52 nmol/s/g) by ~60-fold. The results suggest that palmitate incorporation and turnover in brain phospholipids are far more rapid than generally assumed and that this rapid turnover dilutes tracer specific activity in brain palmitoyl-CoA pool owing to release and recycling of unlabeled fatty acid from phospholipid breakdown.
KW - AcylCoA
KW - Brain
KW - Fatty acids
KW - Palmitate incorporation
KW - Phospholipid metabolism
KW - Rat
UR - http://www.scopus.com/inward/record.url?scp=0028826404&partnerID=8YFLogxK
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C2 - 7595518
AN - SCOPUS:0028826404
SN - 0022-3042
VL - 65
SP - 2290
EP - 2298
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
IS - 5
ER -