Isotopic Renal Function Studies in Severe Hypothyroidism and after Thyroid Hormone Replacement Therapy

We did not find any influence of thyroid hormones on the outcome of (99m )Tc-MAG(3) renography. As (99m)Tc-MAG(3) reflects the tubular function, it seems that the renal hemodynamic changes in severe hypothyroidism mainly affect the glomerular function. In general, the glomerular filtration rate reduction seems to be reversible after hormone substitution therapy; however, care has to be taken in patients with renal insufficiency.