The electrogenic, Na+-dependent I- transport system in plasma membrane vesicles from thyroid glands.
Using vesicles from the plasma membrane of hog thyroid, we have characterized its Na+-dependent I- transport system. We have found it to be totally Na+ dependent; K+ cannot substitute and Li+ can partially substitute for Na+; the Na+:I- flux ratio is larger than one; the system is electrogenic, being stimulated by a delta psi negative inside the vesicles. A number of large, lipophilic anions are fully-competitive inhibitors of Na+-dependent I- uptake; the closer their atomic radii are to that of iodine, the smaller their Ki values.
D000818:Animals; D000838:Anions / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D002412:Cations / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D007455:Iodine / Q000378:metabolism*; D007700:Kinetics; D012964:Sodium / Q000378:metabolism*; D013552:Swine; D013961:Thyroid Gland / Q000378:metabolism*; D014634:Valinomycin / Q000494:pharmacology
D000838:Anions; D002412:Cations; D014634:Valinomycin; D007455:Iodine; D012964:Sodium