Relative increase of serum reverse T3 in patients with hypothyroidism.

ABSTRACT

In 17 hypothyroid patients serum T3 rT3 ratio was 7.5 /+- 1.1 which was significantly lower than in control subjects (12.2 /+- 0.6; p less than 0.001). The data suggest that in hypothyroidism the organism might shift conversion of T4 from biologically active T3 to biologically inactive rT3 which may not be a defense mechanism of the body, as it was found in chronic systemic illness.