TSH Stimulation of14C-Amino Acid Incorporation Into Protein by Isolated Bovine Thyroid Cells

Abstract

The stimulatory action of TSH on C14-leucine and C14-tyrosine incorporation into protein by isolated bovine thyroid cells was investigated. When the cells were preincubated with actinomycin D so that RNA synthesis was severely inhibited, the TSH stimulation of protein synthesis was not greatly impaired. Hence, this action of TSH is not dependent on increased template RNA synthesis. Basal and TSH-stimulated levels of C14-leucine incorporation could be depressed by omission of exogenous glucose. Furthermore, basal C14-leucine incorporation was severely depressed and TSH stimulation was abolished when endogenous glucose metabolism was inhibited with 2-deoxyglucose. Therefore, it is concluded that the TSH effect on protein synthesis could be secondary to its stimulation of glucose metabolism.