In vivo Metabolism of 14C-Labeled Palmitic Acid in Serum and in Brown and White Adipose Tissues of Well-Fed and Starved Newborn Rabbits I.

Abstract

After i.v. injection of 20.106 cpm/100 g body weight 14C-1-palmitic acid at a thermoneutral environment (Ta 35 °C) the primary FFA pool was in 7 days old well fed rabbits (Group I) 9,57 µmole and in rabbits of the same age but previously starved for 48 h at 20 °C (group II) 3.17 and in those starved 72 h at 35 °C (group II) 1.89. There was no significant difference in disappearance rate (λ) half time (t0.5) and turnover time (tt) indicating that the rate at which the label disappeared from the forerunner FFA pool was more dependent on the Ta maintained during the tracer kinetic experiment, than on the duration and the thermal conditions of the previous starvation. The absolute turnover rate of serum FFA (ms) was 9.38 µmole FFA/min in group I and 3.44 and 2.67 in group II and group III, respectively; pointing out that the transfer of FFA from the forerunner pool into the fatty acid compartments of various organs and tissues was significantly reduced by starvation.