Absorption of Herbicides From the Rat Lung

Abstract

To investigate the absorption of some herbicide compounds from the rat lung, 0.1 ml of a solution of compound (0.01 to 10 millimolar) in Krebs-Ringer phosphate solution (pH 7.4) was administered to anesthetized animals by way of a catheter introduced through a tight-fitting tracheal cannula. After various times, lungs were assayed for unabsorbed compound. The times, in minutes, necessary for 50% absorption were: 2,4-dichlorophenoxyacetic acid (2,4-D), 1.4; 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 1.7; 3-amino-1,2,4-triazole (amitrole), 2.0; and diquat, 51. Comparison of absorption rates with concentrations, molecular weights, and lipoid solubilities of the compounds suggested that the results are consistent with the idea that absorption occurs by diffusion across a lipoid-pore type membrane.