title: Penetration of [3H] tiazofurin into guinea pig eye by a saturable mechanism.
abstract: This study investigated the transport of tiazofurin (2-beta-D-ribofuranosyl thiazole-4-carboxamide) across the blood-aqueous humor barrier, using the vascular perfusion method in the guinea pig. Volume of distribution (Vd) of [3H] tiazofurin increased almost linearly in time, from 4% of its plasma concentration at 3 min to 10% after 12 min of perfusion. Unidirectional transport constant, K(in) was 7.01 +/- 1.06 x 10(-3) ml/min/g. These results indicate that tiazofurin penetrates the aqueous humor to a considerable extent. Addition of unlabelled tiazofurin to the perfusing medium caused a significant decrease in the uptake of [3H] labelled tiazofurin (K(in) = 2.60 +/- 0.91 x 10(-3) ml/min/g). Therefore, penetration of tiazofurin from blood into aqueous humor seems to be a saturable process with a diffusional component that cannot be disregarded. Such findings could be of considerable importance since this molecule is known to affect tissue metabolism.
authors.affiliation: Institute of Biochemistry, Faculty of Medicine, Belgrade.
authors.forename: Z B
authors.initials: ZB
authors.lastname: Redzić
authors.forename: I D
authors.initials: ID
authors.lastname: Marković
authors.forename: S S
authors.initials: SS
authors.lastname: Jovanović
authors.forename: B V
authors.initials: BV
authors.lastname: Zloković
authors.forename: L M
authors.initials: LM
authors.lastname: Rakić
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000493:pharmacokinetics*; D001082:Aqueous Humor / Q000378:metabolism*; D001692:Biological Transport; D001813:Blood-Retinal Barrier; D005123:Eye / Q000378:metabolism*; D006168:Guinea Pigs; D006207:Half-Life; D010477:Perfusion; D012254:Ribavirin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
chemical_list: D000970:Antineoplastic Agents; D012254:Ribavirin; C033706:tiazofurin