Organic acids as metabolic indicators. III. The metabolism of 14C-propionate in rats exposed to irradiation and thermal injuries

Abstract: 14C-propionate utilization was found to be a useful in vivo indicator of the severity of burn or irradiation injuries and the extent of recovery from such injuries. Flash burns (9.2 cal/sq cm, 30 percent of body area) or gamma irradiation (750 rad) produced a significantly reduced rate of 14CO2 production from 1-14C propionate during the initial shock phase following exposure. Recovery from nonlethal injuries was associated with recovery to ability to oxidize propionate within 1 to 2 weeks. In the case of animals exposed to irradiation plus flash burns, a greater initial decrease in propionate oxidation was noted and recovery did not occur. The persistence of decreased rates of propionate oxidation often was correlated with early mortality. It was concluded that a deficiency of Krebs' cycle intermediates was a significant characteristic of the initial metabolic state or 'evv' following injuries and that biochemical events sensitive to irratiation were involved in recovery. Measurements of the rate and pathway of propionate utilization appeared to be a useful physiological monitor for estimating the extent of recovery from thermal burns. (Author)