Abstract
The urinary excretion of hydroxyproline, the amino acid specifically existent in collagen, is considered to be a reliable indicator of metabolic status of collagen, including bone matrix turnover (Prockop and Kivirikko, 1967). The increase of hydroxyproline in the daily output is found in various diseases, which influence the bone formation or resorption (Platt et al., 1964; Basu et al., 1974; Yumita, 1983). It has been proved that, for breast and prostatic cancers, the urinary excretion of hydroxyproline is not only an accurate index of skeletal involvement, but also a useful indicator to evaluate the evolution of metastatic bone disease while the patient is on therapy (Bishop· and Fellow, 1977; Niell et al., 1983). Iguchi and Sano reported an increase of the urinary hydroxy proline excretion in patients with ItaiItai disease (1974). However, it is not yet clear whether or not, the urinary hydroxyproline excretion really increase in the stage prior to the development of chronic cadmium poisoning. This paper shows the urinary levels of hydroxyproline among the inhabitants of the present area, Annaka City, where their urinary levels of cadmium was higher than those of non-polluted area. But no serious effects were observed due to the environ mental cadmium exposure.
