[Effects of TSH on thyroid ribonucleic acids (author's transl)]

Bovine thyroid slices were incubated with TSH (20 mU/ml) in the presence of 0.04 microgram/ml actinomycin D. The incorporation of 3H Adenosine or 3H Uridine in the microsomal RNA fraction was studied. TSH enhanced the labeling of this RNA. After gel electrophoresis in 100% formamide, the distribution of the radioactivity showed a relatively larger incorporation of the precursors in the region corresponding to heavy molecular weight RNA (3 X 10(6) daltons). These data suggest that TSH could exert a specific effect on transcription in the thyroid gland.