Role of unstirred layer in intestinal absorption of phenylalanine in vivo.
The appearance rate of L- and D-phenylalanine in the venous blood of rat jejunal loops in vivo is increased up to 60% if the intraluminal solution is mixed more efficiently by the simultaneous perfusion of air. The effect decreases as the luminal concentration is increased to 100 mmol/l. Thus, the apparent Michaelis constants are by 50% lower in the case of the reduced unstirred layer (26 to 17 for L- and 9 to 6 mmol/l for D-phenylalanine). The enhancement of the absorption and the reduction of the Michaelis constants can be attributed to the reduction of the effective unstirred layer thickness by about 400--500 micrometer.
D000388:Air; D000818:Animals; D007408:Intestinal Absorption; D007583:Jejunum / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008954:Models, Biological; D010477:Perfusion / Q000379:methods; D010649:Phenylalanine / Q000097:blood / Q000378:metabolism*; D051381:Rats; D012996:Solutions
D012996:Solutions; D010649:Phenylalanine