Acute in vitro thyrotropin regulation of lysosomal enzyme activity in the thyroid follicular cell

Abstract The acute effect of a physiological concentration (1 mU/1) of thyrotropin (TSH) on the activity of four lysosomal enzymes in the thyroid follicular lining cell has been studied by quantitative cytochemical techniques. N -acetyl-β-glucosarninidase (NAG) activity was increased by 14% after 10 min TSH stimulation and NAG and β-galactosidase activities were increased by 24% and 25% respectively ( P P In conclusion we have demonstrated for the first time with physiological concentrations of TSH a specific acute regulation of some lysosomal enzyme activities which may be involved in thyroglobulin processing. Further, these effects may be independent of the changes in lysosomal membrane permeability due to formation of secondary lysosomes.