title: Biological distribution of 99mTc-labeled YIGSR and IKVAV laminin peptides in rodents: 99mTc-IKVAV peptide localizes to the lung.
abstract: Two laminin-derived peptides containing either YIGSR or IKVAV (single amino acid code) sequences were radiolabeled with 99mTc and their biological distribution evaluated in rodents. Both 99mTc-peptides cleared rapidly from the circulation though the kidney, and to a lesser extent, through the liver. 99mTc-YIGSR peptide did not accumulate in any organ examined in normal, tumored, and emphysemic mice. The 99mTc-IKVAV peptide localized within 10 min to the lung of normal animals, resulting in lung-to-blood ratios of approximately 23:1. The 99mTc-IKVAV peptide localized to lung after submicron filtration and after intraperitoneal injection, suggesting that particulates do not major role in localization. Pre-incubation of 99mTc-IKVAV peptide in whole blood decreased lung localization, suggesting that margination of radiolabeled cells does not play a major role in the lung localization. When 99mTc-IKVAV was injected into mice with tumored lungs (melanoma), the lung uptake was markedly increased (up to 20% injected dose higher than control lungs) at all time points examined (10, 30, and 120 min). When 99mTc-IKVAV was injected into mice with genetic emphysema, the lung uptake was markedly decreased at all time points. The localization of the 99mTc-IKVAV-containing peptide to the lung is consistent with a receptor-based mechanism.
authors.affiliation: RhoMed Incorporated, Albuquerque, NM 87109.
authors.forename: P O
authors.initials: PO
authors.lastname: Zamora
authors.forename: D
authors.initials: D
authors.lastname: Eshima
authors.forename: D
authors.initials: D
authors.lastname: Graham
authors.forename: L
authors.initials: L
authors.lastname: Shattuck
authors.forename: B A
authors.initials: BA
authors.lastname: Rhodes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004646:Emphysema / Q000378:metabolism; D005260:Female; D007553:Isotope Labeling; D007797:Laminin / Q000493:pharmacokinetics*; D008168:Lung / Q000378:metabolism*; D008545:Melanoma / Q000378:metabolism; D008657:Metabolic Clearance Rate; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013667:Technetium; D014018:Tissue Distribution
chemical_list: D007797:Laminin; D010446:Peptide Fragments; D013667:Technetium