title: Distribution and elimination characteristics of 111In-DTPA-D-phe1-octreotide and 111In-DTPA-L-phe1-octreotide in rats.
abstract: The present study compares distribution and elimination characteristics of 111In-DTPA-D-Phe1-octreotide and 111In-DTPA-L-Phe1-octreotide in rats and evaluated the effect of the replacement of the terminal L-phenylalanine by D-phenylalanine on pharmacokinetic profiles of the radiolabelled peptides. Both agents exhibited rapid radioactivity clearance from the blood and most organs and tissues with no systematic and significant differences in activity accumulation. The long-term retention and high radioactivity concentrations for both compounds under study were found in the kidneys and organs with a high density of somatostatin receptors, such as the pancreas and adrenals. The residence times in these organs were longer for 111In-DTPA-D-Phe1-octreotide in comparison with 111In-DTPA-L-Phe1-octreotide. The major elimination pathway for both radiolabelled peptides was relatively rapid excretion into the urine. Analysis of the renal handling by an employment of the perfused rat kidney showed that both peptides were eliminated mainly by the mechanism of glomerular filtration. Rat liver perfusion experiments confirmed a very low value of bile clearance of radioactivity for both agents under study.
authors: Faculty of Pharmacy, Charles University with the Research Centre Hradec Kralove, Czech Republic.
authors: Alice
authors: A
authors: Laznickova
authors: M
authors: M
authors: Laznicek
authors: F
authors: F
authors: Trejtnar
authors: L
authors: L
authors: Melicharova
authors: Kazuko Horiuchi
authors: KH
authors: Suzuki
authors: Hiromichi
authors: H
authors: Akizawa
authors: Yasushi
authors: Y
authors: Arano
authors: Akira
authors: A
authors: Yokoyama
mesh_terms: D000818:Animals; D001646:Bile / Q000737:chemistry; D007205:Indium Radioisotopes; D007275:Injections, Intravenous; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D015282:Octreotide / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics* / Q000652:urine; D004369:Pentetic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics* / Q000652:urine; D019275:Radiopharmaceuticals / Q000737:chemistry / Q000493:pharmacokinetics* / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism; D014018:Tissue Distribution
chemical_list: D007205:Indium Radioisotopes; D019275:Radiopharmaceuticals; C071632:SDZ 215-811; D004369:Pentetic Acid; D015282:Octreotide