Effect of lactic acid on postprandial plasma-glucose and -insulin responses in rats administered glucose solution

Abstract

The effect of lactic acid or sodium lactate on the glycemic response was studied in rats. The lightly anesthetized, overnight-fasted rats were administered a glucose solution (200 g/L) with or without lactic acid or sodium lactate by a stomach tube to provide 250 mg of glucose per 100 g body weight. The addition of lactic acid (300 mmol/L) to a glucose solution reduced the initial rise in plasma glucose and insulin concentrations, slowed the rate of gastric emptying and brought a drop of pH in gastric contents. However, such effects were not recognized in the addition of sodium lactate (300 mmol/L as the lactate ion). Lactic acid stimulated cholecystokinin (CCK) and secretin release, but inhibited gastrin release. The study suggests that lactic acid is effective in modulating postprandial plasma glucose concentration, which is due to delayed gastric emptying accompanied by the increase of secretin and CCK release following the fall in intraduodenal pH.