[Behavior of serum angiotensin converting enzyme in hyperthyroidism correlated to that of TSH].

The study examined the relations between serum levels of angiotensin-converting enzyme and those of thyroid-stimulating hormone in a group of hyperthyroid patients, and the respective therapy. The study continued for 12 months, from the onset of disease until remission. From an analysis of the results it was seen that levels of SACE and TSH during the first 4 months were significantly different to those in normal subjects: levels of SACE were increased, whereas TSH levels had fallen. This difference gradually diminished over the course of the following 8 months, and SACE and TSH values returned to within normal limits. The increment of SACE may depend on the presence of damage to the vascular endothelium within and surrounding the thyroid, in addition to intense vasodilation caused by the hyperthyroid state. The correlation between increased SACE levels and the course of disease is further confirmed by the fact that levels returned to within normal values during thyrostatic therapy; this was also observed in the case of TSH.