Decreased serum beta-D-mannosidase activity in diabetic patients, in comparison with other glycosidases.

A study of four lysosomal glycosidases' activities was carried out on sera from 64 diabetic patients, which revealed important variations in comparison with the activities observed in sera of control subjects. Depending on the type of diabetes mellitus (I, insulin-dependent, or II, non-insulin-dependent), three activities were more or less increased: alpha-L-fucosidase, alpha-D-mannosidase, and N-acetyl-beta-D-glucosaminidase, in agreement with previously published results. Against that, the beta-D-mannosidase activity shows a highly significant decrease in sera from either diabetic type. Up to now, no suitable explanation has been found for these variations occurring in an unusual direction.