title: Transport mechanism of some naturally occurring tetracyclines across everted rat gut.
abstract: Naturally occurring tetracycline antibiotics were tested for active transport in a standard everted rat gut preparation. The ratio of drug concentrations between serosal and mucosal solutions was measured as well as the rate of transport at different mucosal concentrations. Although a ratio of near unity was demonstrated by all the antibiotics, indicating passive transport, the rate of transport was linear only at low concentrations. A mechanism of more than simple diffusion was suggested. A carrier with limited capacity present in the intestinal tissue might be responsible for the transport of these antibiotics.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D066298:In Vitro Techniques; D007408:Intestinal Absorption; D051381:Rats; D012995:Solubility; D013500:Surface Tension; D013754:Tetracyclines / Q000378:metabolism*; D013997:Time Factors
chemical_list: D013754:Tetracyclines