Significant increase of urinary mucoprotein in environmental-cadmium-exposed Japanese subjects

Abstract Urinary mucoprotein(U-MP) was determined in 169 Japanese environmental-cadmium- exposedand 81 non- exposedsubjects. Urinary total protein, albumin, β 2 -microglobulin (β 2 -MG), cadmium (Cd) and creatinine were also measured. Significant increases in U-MP and other proteins were found in the Cd- exposedsubjects. Significant correlations between each protein were seen in the Cd- exposedand the total group of subjects. U-MP was highly correlated with urinary β 2 -MG and their correlation coefficient was the highest in the total group of subjects. β 2 -MG was the most sensitive indicator among them to detect Cd-induced renal dysfunction, although β 2 -MG is degraded in urine with a pH less than 5.5. U-MP is an acid-soluble protein. Therefore, U-MP is also available for studies on renal dysfunction caused by exposure to Cd, in conjunction with β 2 -MG.