Value of urine and serum hydroxyproline in the diagnosis of thyroid disease.

Abstract

The excretion of free and total hydroxyproline in the urine and the concentration of free hydroxyproline in the serum were determined in 32 patients with hyperthyroidism, in 10 patients with hypothyroidism and in 32 control subjects. All 3 hydroxyproline values were increased in hyperthyroidism and decreased in hypothyroidism, but the values for urinary free hydroxyproline showed a considerably greater overlap with the controls than the other 2 values. The excretion of total hydroxyproline was within the range of the values of the control subjects in none of the patients with hypothyroidism and in only 2 very mild cases with hyperthyroidism, in both of whom this value was right at the upper limit of the range of the control values. A statistically highly significant correlation was found between the values for urinary total hydroxyproline and serum protein-bound iodine. Therapy was accompanied by a rapid normalization of the hydroxyproline values. It is suggested that the determination of urinary total hy...