Radiolabeled somatostatin analogs in prostate cancer.
Vapreotide (RC-160), a somatostatin analog, was labeled with 99mTC by a direct method and also by using CPTA [1,4,8,11-tetraazacyclotetradecane] as a bifunctional chelating agent. The labeled compounds were evaluated in nude mice bearing experimental human prostate cancers. In these studies, 111In-DTPA-D-Phe-Octreotide (111In-DTPA-octreotide) served as a standard and 99mTc-oxytocin as a receptor-non-specific control. 99mTc-octreotide was also used. The 24 htumor uptake of 99mTc-RC-160 was nearly 400% higher, (p < 0.05), than that of 111In-DTPA-octreotide and diminished upon receptor blocking. In all tissues except the kidneys, the uptake of 99mTc-RC-160 was also higher than that of 111In-DTPA-octreotide. The uptake of 99mTc-RC-160 was influenced by the amount of peptide injected and the best tumor/muscle and tumor/blood ratios were obtained when only one micrograms of the peptide (200 Ci/mmol) was administered.
Thakur
M L
ML
Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA. thakur1@jeflin.edu.tju
Kolan
H
H
Li
J
J
Wiaderkiewicz
R
R
Pallela
V R
VR
Duggaraju
R
R
Schally
A V
AV
D000818:Animals; D000970:Antineoplastic Agents / Q000493:pharmacokinetics*; D018931:Antineoplastic Agents, Hormonal / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D015282:Octreotide / Q000493:pharmacokinetics; D010121:Oxytocin / Q000494:pharmacology; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000378:metabolism; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D017556:Technetium Compounds / Q000493:pharmacokinetics; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured / Q000378:metabolism*
D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; D017481:Receptors, Somatostatin; D017556:Technetium Compounds; C051458:vapreotide; D010121:Oxytocin; D013004:Somatostatin; D015282:Octreotide