The effect of ionizing irradiation on the oxidation of palmitate-1-14C by thymus and liver.
New Zealand rabbits, fasted for 12 hours, were subjected to 500 rads of whole-body irradiation. K+-palmitate-1-14C oxidation was assayed with the 600 X g supernatant of thymus and liver homogenates, in the presence of ATP, at various time intervals from irradiation. For a period of 24 hours following irradiation, oxidation by liver preparations was not significantly affected. The rate of oxidation by thymus was decreased to less than one-third of the control value within 12 hours from irradiation and, at 24 hours, was almost completely abolished. Increased ATP concentration could increase only to a small extent the oxidation by thymus preparations of irradiated animals. Oxidation by isolated thymus mitochondria was also inhibited by irradiation. Counting of the water-soluble oxidation products of palmitate-1-14C suggests that the inhibition is not due to the impairment of the reactions of the citric acid cycle. The non-esterified fatty acid concentration of thymus was not altered at 12 hours following irradiation. Esterification of K+-palmitate-l-14C into the thymus lipids was not affected 12 hours after irradiation.
Miras
C J
CJ
Biochemical Research Laboratory, School of Medicine, University of Athens, Athens, Greece.
Mantzos
J D
JD
Legakis
N J
NJ
Levis
G M
GM
D000818:Animals; D002250:Carbon Radioisotopes / Q000378:metabolism; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D005260:Female; D008099:Liver / Q000378:metabolism* / Q000528:radiation effects*; D008297:Male; D008928:Mitochondria / Q000378:metabolism* / Q000528:radiation effects*; D010084:Oxidation-Reduction / Q000528:radiation effects; D010168:Palmitates / Q000378:metabolism*; D011817:Rabbits; D011829:Radiation Dosage; D013950:Thymus Gland / Q000378:metabolism* / Q000528:radiation effects*; D014916:Whole-Body Irradiation
D002250:Carbon Radioisotopes; D010168:Palmitates