Influence of the neonatal suppression of TSH production (neonatal hyperthyroidism) on response to TSH in adulthood.

Six-day treatment of neonatal rats with T3 or T4 resulted in a considerable depression of T4 production in response to exogenous TSH in adulthood. This supports the hypothetical conclusion that hormonal imprinting, i.e. the presence of the hormone and its interaction with the cell during the period of receptor maturation, is important for receptor amplification, which accounts for normal response to the hormone in adulthood.