Active absorption of hypoxanthine by lamb jejunum in vitro.
The kinetics of [3H]hypoxanthine entry into lamb mid-jejunum were measured using 2-min mucosal exposures. Mucosal hypoxanthine uptake occurred by a Na+- and energy-dependent saturable mechanism indicating that a carrier-mediated active transport process is involved. Inhibitory measurements indicate that hypoxanthine, adenosine, uracil and thymine complete for a common entry mechanism. Adenine, uric acid, allantoin and thymidine produced no significant inhibition of hypoxanthine entry. In additional experiments hypoxanthine was transported against a high concentration gradient from the mucosal to the serosal side of everted sacs of mid-jejunum. Therefore hypoxanthine appears to be absorbed by active transport from the lamb jejunum.
D000818:Animals; D001693:Biological Transport, Active; D007042:Hypoxanthines / Q000378:metabolism*; D066298:In Vitro Techniques; D007583:Jejunum / Q000378:metabolism*; D011687:Purines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D012756:Sheep / Q000502:physiology*; D013997:Time Factors
D007042:Hypoxanthines; D011687:Purines; D011743:Pyrimidines; C030985:purine