Regional cerebral incorporation of plasma [14C]palmitate, and cerebral glucose utilization, in water-deprived Long-Evans and Brattleboro rats.
Regional rates of incorporation into brain of intravenously administered [14C]palmitate and regional cerebral metabolic rates for glucose (rCMRglc) were measured in water-provided (WP) and water-deprived (WD) homozygous (DI) and heterozygous (HZ) Brattleboro rats, a mutant strain unable to synthesize vasopressin, and in the parent Long-Evans (LE) strain. Following 15 h or 4 days of water deprivation, rCMRglc was elevated threefold in the pituitary neural lobe of LE-WD and DI-WD as compared with LE-WP rats, and in the paraventricular nucleus of LE-WD, and the supraoptic nucleus of DI-WD rats. However, incorporation of [14C]palmitate into these regions was not specifically altered. The results indicate that water deprivation for up to 4 days increases rCMRglc in some brain regions involved with vasopressin, but does not alter [14C]palmitate incorporation into these regions. Incorporation of plasma [14C]palmitate is independent of unlabeled plasma palmitate at brain regions which have an intact blood-brain barrier, but at nonbarrier regions falls according to saturation kinetics as cold plasma concentration rises, with a mean half-saturation constant (Km) equal to 0.136 mumol.ml-1.
Noronha
J G
JG
Laboratory of Neurosciences, National Institute on Aging, Bethesda, Maryland 20892.
Larson
D M
DM
Rapoport
S I
SI
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002250:Carbon Radioisotopes; D005947:Glucose / Q000378:metabolism*; D006579:Heterozygote; D006720:Homozygote; D010168:Palmitates / Q000097:blood / Q000378:metabolism*; D010169:Palmitic Acids / Q000378:metabolism*; D051381:Rats; D011910:Rats, Brattleboro; D011919:Rats, Inbred Strains; D012016:Reference Values; D014868:Water Deprivation
D002250:Carbon Radioisotopes; D010168:Palmitates; D010169:Palmitic Acids; D005947:Glucose