Turnover Time of Lecithin in Lung Tissue and Alveolar Wash of Rat

Abstract

Turnover time of tissue and alveolar lecithins of rat lung was determined according to the decay curve of radioactivity as well as the precursor-product relationship by Zilversmit's equation, from specific activity of lecithin and its subspecies after intravenous injection of ³H-palmitate, ¹⁴C-glycerol and ³H-choline. The turnover times of alveolar lecithins were 5.1 hours with ³H-palmitate, 5.6 hours with ¹⁴C-glycerol and 14.9 hours with ³H-choline, respectively, from the calculation according to Zilversmit's equation. The turnover times of tissue lecithins were determined as 20.5 hours, 19.8 hours and 67.7 hours, respectively, from their half lives. Certain aspects regarding turnover rate of lecithin in lung tissue as well as its secretion rate into alveolar cavity were discussed using the data reported by other investigators as well as our present data.