“Like CH, actinomycin D (ActD), added at the beginning of the 48-h period, inhibits TSH induction of I- uptake; partial inhibition (83%, 72%, and 28%) is observed when ActD is added at 1, 5, and 10 h, respectively.”
“Treatment with ActD at 24 h (ActD-treated cells), however, paradoxically increases I- uptake (1.8- to 3.5-fold over the control value).”