Triiodothyronine receptors in lymphocytes of newborn and adult rats.

Cytoplasmic and nuclear incorporation of 125I triiodothyronine by thymic lymphocytes has been demonstrated by electron microscopic autoradiography. Incorporation was significantly more pronounced in the newborn than in the adult age. The information emerging from the experime,tal observations contributes further evidence to the more precise interpretation of receptor maturation.