Colonic absorption of vitamin K-3
Hollander, D.; Truscott, T.C.
Journal of Laboratory and Clinical Medicine 83(4): 648-656
1974
ISSN/ISBN: 0022-2143 PMID: 4817784 Document Number: 70902
Segments of colon from male Sprague-Dawley rats fed to appetite on stock diet were everted and perfused. Stepwise increases in mucosal menaquinone concentration up to 900 mu M resulted in linear increase in transport rate. Basal absorption rate of the vitamin under oxygen at 300 mu M mucosal concentration was 10.99 plus or minus 0.59 nmol/min 100 g dry tissue. The transport rate did not decrease under nitrogen or in the presence of 10-4 M 2,4-dinitrophenol or 3 X 10-3 M sodium azide. With the same experimental preparation, octanoate was transported across the colon, but the water-soluble alcohol, erythritol, was not. Transport ceased in absence of a concentration gradient across the colonic mucosa. It is concluded that the metabolically active nucleus of vitamin K is absorbed in rat colon by a passive transport mechanism.