[Thyroid function in the nephrotic syndrome].

Serum Total Thyroxine (T4), Triiodothyronine (T3), Free Thyroxine (FT4), Free Triiodothyronine (FT3) Reverse Triiodothyronine and T3 Resin Uptake (T3RU) as well as basal and post stimulating TSH were measured in twenty clinically euthyroid patients with the nephrotic syndrome. In comparison with control values, our patients showed (1) significantly lowered mean serum TBG levels (p less than 0,05) (2) unmodified mean serum T3, FT3 and rT3 values (3) significantly lowered mean serum T4 and FT4 levels (p less than 0,001 and p = 0,027 respectively) (4) significantly higher mean basal TSH, and increased TSH response to TRH. We found a significant correlation between proteinemia and T4 or FT4 (p less than 0,001; p less than 0,01 respectively). In summary, our study: Shows that the low Total T4 observed in the Nephrotic Syndrome is not only due to a decreased protein bound T4, but also to a decreased FT4; And brings evidence for mild hypothyroidism in nephrotic patients.