[Principals of hormone substitution in thyrectomized patients with carcinoma of the thyroid gland (author's transl)].

The substitution of thyrectomized patients with carcinoma of the thyroid with L-thyroxin has advantages compared to a substitution with triiodothyronine, 200 mug T4/d are sufficient to obtain a negative TRH test in most patients. For security it is suggested to performe a general substitution of these patients with 300 mug T4/d. This dose is very well tolerated. To high doses of substitution cause a "damage" of the thyreotrop in a part of the patients. This is demonstrated by a transient thyreotropic insufficiency after withdrawal of the substitution. The results demonstrated here suggest that the central suppression of TSH secretion is better correlated with plasma T4 than plasma T3 levels.