Adenosine deaminase activity and zinc levels in the serum of patients with diabetes mellitus

Objective: Adenosine deaminase (ADA) specifically catalyzes the deamination of adenosine which has been proved to play an important role in modulation of insulin action on glucose metabolism. Zinc is an essential micronutrient that is directly involved in the physiology of insulin and may be an important agent to activate the ADA. We aimed to evaluate serum ADA activity, zinc levels and the relationship between these two parameters in diabetes mellitus. Methods: We investigated serum ADA activity and zinc levels in type I (n = 100) and type II diabetes mellitus patients (n = 151). Results: ADA activities of diabetic patients were significantly elevated, whereas zinc levels were significantly lower than those of healthy controls (p < 0.001). Compared with the well-controlled diabetic patient groups (HbA(1c) < 7%), the poorly controlled diabetic groups (HbA(1c) > 8%) showed significantly increased ADA activity (p < 0.001). In contrast, zinc concentrations in the poorly controlled diabetic groups were not significantly different from those in the well-controlled diabetic patients (p = 0.246). Significant positive correlation was observed between ADA activity and HbA(1c) (r = 0.794). There was no correlation between ADA activity and zinc levels (r = 0.043; p > 0.05). Conclusion: Elevated ADA activity in diabetic patients with poor glycemic control may be a useful marker for therapy modulation.