Hydroxyproline Excretion in the Urine and Calcium Metabolism During Long‐term Treatment of Thyrotoxicosis With Propylthiouracil

Thirty hyperthyroid patients have been studied before and during long‐term treatment with propylthiouracil for the purpose of evaluating changes in the excretion of urinary hydroxyproline and relating these to some parameters of calcium metabolism and thyroid function. Urinary hydroxyproline and urinary calcium were found to be significantly raised before treatment. A very rapid fall in urinary calcium was noted within the first two weeks of treatment. BMR and PBI showed a parallel fall to euthyroid values following six weeks of treatment, while there was a slow fall in the mean value of urinary hydroxyproline. After three months the mean value was still elevated and normal values of urinary hydroxy‐proline were not obtained until six months after the beginning of treatment. A possible causal relation between collagen metabolism and calcium metabolism during antithyroid treatment is discussed. Our results may indicate that many hyperthyroid patients do not reach a metabolic steady state until about three months after the beginning of antithyroid treatment.