[Behavior of the levels of free triiodothyronine, triiodothyronine, free thyroxine, thyroxine, thyrotropin and thyroxine-binding globulin in the serum of children with nephrotic syndrome].

Concentrations of free triiodothyronine, triiodothyronine, free thyroxine, thyroxine, thyrotropin, thyroxine-binding globulin, urea, creatinine, cholesterol and total protein were determined in serum of four children (ages from 8 to 16 years) with nephrotic syndrome undergoing therapy. The results showed that at serum protein concentration of less than 4.5 g/dl the concentration of free thyroxine was 3.35 +/- 2.32 pg/ml and that of free triiodothyronine 2.65 +/- 0.96 pg/ml. Elevation of the protein concentration to 4.5-5.7 g/dl lead to an increase in the concentration of free thyroxine to 6.53 +/- 3.69 pg/ml and of free triiodothyronine to 3.32 +/- 1.08 pg/ml. The age-matched reference values for free thyroxine are 15.72 +/- 1.9 pg/ml and for free triiodothyronine 5.10 +/- 1.29 pg/ml. The concentration of thyroxine, triiodothyronine and thyroxine-binding globulin were decreased whereas that of thyrotropin was elevated. Although free triiodothyronine and triiodothyronine were decreased they remained close to the normal range thus preventing apparent hypothyroidism. Improvement in the concentration of serum protein and cholesterol lead to an improvement of serum levels of thyroid hormones and thyroxine-binding globulin; concentrations of thyrotropin remained elevated.