Low protein supplemented diet corrects altered serum thyroid hormone and TSH concentrations in patients with chronic nephrotic syndrome.

Creatinine clearance, daily urinary protein excretion, serum concentrations of thyroid hormones (TT4, TT3, fT4, fT3), TSH and parathyroid hormone (PTH), have been measured before and after 2 or 6 months of a low protein diet supplemented with aminoacids and ketoanalogues in 18 patients affected by chronic nephrotic syndrome without significant impairment of renal function. Mean creatinine clearance and mean serum protein concentration (79.5 +/- 13.8 ml/min and 5.4 +/- 0.6 g/dl, mean +/- S.D., respectively) did not significantly change (79.1 +/- 17.3 ml/min and 5.5 +/- 0.6 g/dl) after the diet. Mean daily urinary protein excretion (7.1 +/- 2.2 g/day basally) significantly decreased (5.5 +/- 1.9 g/day) after the diet (p less than 0.05). Mean serum TT4 concentration (5.6 +/- 1.8 micrograms/dl basally) significantly increased (6.7 +/- 2 micrograms/dl, p less than 0.05) after the diet. Mean serum TT3 concentration (106.7 +/- 28.5 ng/dl, basally) significantly increased (126.7 +/- 22.6 ng/dl) after the diet (p less than 0.01). Mean serum fT4 and fT3 concentrations (8.0 +/- 2.9 pg/ml and 4.5 +/- 1.6 pg/ml, respectively) did not significantly change (9.4 +/- 2.7 pg/ml, and 4.9 +/- 1.9 pg/ml, respectively) after the diet. In some patients low basal serum concentration values of TT4, TT3, fT4, fT3 became normal after the diet. Mean serum TSH concentration (3.1 +/- 2.3 microU/ml basally), significantly decreased (1.5 +/- 1.3 microU/ml) after the diet (p less than 0.05). Mean serum PTH concentration (0.7 +/- 0.3 ng/ml basally) significantly decreased (0.4 +/- 0.2 ng/ml) after the diet (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)