Alteration of glucose tolerance by dietary L-tryptophan in rats.
L-Tryptophan is known to have pharmacological effects on carbohydrate metabolism. In a scrutiny for possible physiological relationships, intravenous glucose tolerance was measured in rats fed various diets of defined L-tryptophan-content. Within 14 days, animals which had been fed a tryptophan-deficient diet diet removed excess glucose from their blood at a reduced rate. This decreased tolerance to glucose was dose dependent to dietary L-tryptophan and the intolerance was reversed by feeding a complete diet. The intolerance was not dependent on dietary protein source, not reversed by added niacin or vitamin B-6, not a necessary consequence of decreased food consumption and growth, and not duplicated by a lack of dietary lysine. The results suggest  that dietary L-tryptophan is active in physiological regulation of carbohydrate metabolism.
D000818:Animals; D050260:Carbohydrate Metabolism; D003677:Deficiency Diseases / Q000188:drug therapy / Q000378:metabolism; D004044:Dietary Proteins; D004305:Dose-Response Relationship, Drug; D005260:Female; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D009539:Nicotinic Acids / Q000494:pharmacology; D011736:Pyridoxine / Q000494:pharmacology; D051381:Rats; D014364:Tryptophan / Q000172:deficiency / Q000494:pharmacology* / Q000627:therapeutic use
D004044:Dietary Proteins; D009539:Nicotinic Acids; D014364:Tryptophan; D005947:Glucose; D011736:Pyridoxine