Rat thyroid peroxidase (TPO) biosynthesis in vitro: studies using antiserum to porcine TPO

Using partially purified trypsin-solubilized porcine thyroid peroxidase (TPO), an antiserum was developed which inhibited enzyme activity in vitro, and which cross-reacted with partially purified rat TPO. Using rat thyroid minces, this antiserum was utilized to detect radiolabeled TPO in vitro. Newly synthesized rat TPO was observed in the presence of TSH (10 mU/ml), an effect which was completely blocked by co-incubation with cycloheximide. TPO biosynthesis was detected within 6 h of incubation, consistent within a rapid effect of TSH on thyroidal protein biosynthesis.