Effect of aspartame on the activity of intraluminal intestinal alkaline phosphatase (IAP) in an isolated bowel loop in mice. When aspartame is instilled in a closed bowel loop, IAP activity is significantly inhibited compared with a saline control (p = 0.02). Values are means ± SE, n = 5. pPNNP, p-nitrophenyl phosphate. *, Significant change from saline baseline, p < 0.05.