RESUMO
The renal osmoregulatory function was studied in patients with type 2 diabetes mellitus (DM). The renal response to water loading (0.7% b.w.) and simultaneous exenatide (byetta) injection (5 microg) exhibited variation and was dependent on the degree of hyperglycemia. Effective solute-free water excretion was observed in patients with well-controlled DM (HbAlc 6.0 +/- 0.1%), in which CH20 changed from -0.67 +/- 0.2 mL/min to 0.72 +/- 0.2 mL/min. This reaction was absent in patients with poorly controlled DM (HbAlc 8.8 +/- 0.6%) and the process of solute-free water reabsorption prevailed: -CH20 = -1.06 +/- 0.1 mL/min in control period vs. -0.99 +/- 0.1 mL/min after treatment. Thus, byetta increases the efficiency of osmoregulation and accelerates the excretion of excess water in patients with compensated carbohydrate metabolism.