Influence of Tris (Hydroxymethyl) Aminomethane on Plasma Insulin and Glucose Concentration of Normal and Streptozotocin-Diabetic Rats

The influence of Tris buffer on plasma glucose and insulin concentrations was investigated in pentobarbital-anesthetized (60 mg/kg i.p.) Wistar rats. A bolus injection of neutralized Tris (5 mmol/kg; pH 7.4) caused a transient increase of plasma insulin concentration (+ 130 ± 20 μU/ml; x ± Sχ, n = 6) but did not change the glucose concentration. A continuous infusion of Tris (0.5 mmol/kg·min for 90 min) reduced the plasma glucose concentration from 8.7 ± 0.42 to 5.1 ± 0.33 mmol/l after 30 min. The plasma insulin concentration was elevated during the first 20 min (maximum + 122 ± 21 μU/ml after 10 min). In streptozotocin-diabetic rats (75 mg/kg i.v., 48 h prior to the experiments) an infusion of Tris changed neither glucose nor insulin concentration in plasma. The results indicate that in the rat Tris-induced hypoglycemia is always associated with a transient stimulation of insulin secretion.