The oxygen uptake of kidney cortex slices of thyroidectomized rats as influenced by triiodothyroacetic acid.

Abstract

SUMMARY Concentrations of triiodothyroacetic acid (TRIAC) of 1·5 × 10-6 m to 4·2 × 10-6 m appear to have an immediate stimulating effect on the oxygen uptake of kidney cortex slices of thyroidectomized rats but inhibit respiration afterwards under the conditions of the experiments described. Such a response could not be demonstrated when TRIAC of final concentrations between 7·0 × 10-7 m and 1·4 × 10-6 m was kept in contact with the slices for about ½ hr at 37° C or at 5° C. The mean QO2 value of kidney cortex slices of thyroidectomized rats maintained on an iodine-deficient diet was appreciably less (4·7) than that of thyroidectomized rats on an ordinary diet (12·4), and such slices from iodine-deficient animals did not respond to concentrations of 6·4 × 10-7 m and 8·0 × 10-7 m solutions of TRIAC. The respiration of kidney cortex slices of thyroidectomized rats was inhibited by TRIAC (10-6 m and 10-7 m) in the presence of bacteria to a greater extent than in their absence provided that the TRIAC was in contact with the material during the period of equilibration. A concentration of 10-8 m TRIAC inhibited the respiration of such slices by 10%, but did not do so in the presence of bacteria. White light illumination did not stimulate the immediate oxygen uptake of kidney cortex slices of thyroidectomized rats.