Examination of methods for the preparation of biologically active radiolabeled melanotropins

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6306266

Heward, C B

The present studies were initiated to develop a radioactive melanotropin with full, or nearly full, biological activity. This labeled melanotropin must be of sufficient specific radioactivity to be suitable as a tracer in a radioreceptor assay and ultimately as a marker for in vivo tumor localization. The studies described herein provide information concerning: chloramine T induced iodination, lactoperoxidase catelyzed iodination, and iodogen induced iodination of ..cap alpha..-MSH and certain structural analogues. Radio-labeled derivatives of various melanotropins were prepared using a variety of iodination techniques. Under conditions commonly used for the iodination of other peptides a substantial loss of biological activity of the native hormone (..cap alpha..-MSH) was observed. Under similar iodination conditions using 4-norleucine-alpha-melanotropin ((NIe/sup 4/)-..cap alpha..-MSH), satisfactory incorporation of label into the peptide was accomplished without significant loss of biological activity. Data are presented suggesting that this peptide is far superior to ..cap alpha..-MSH for use in the preparation of a radioactive melanotropin. Although some success was achieved using (NIe/sup 4/)-..cap alpha..-MSH with all three iodination methods, the simplest and most consistent method involved the use of iodogen followed by purification of the labeled product using high performance liquid chromatography (HPLC).

• Research Organization: Arizona Univ., Tucson (USA)
• OSTI ID: 6306266
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702 -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINES
ANIMAL CELLS
BETA DECAY RADIOISOTOPES
BIOLOGICAL LOCALIZATION
CHEMICAL PREPARATION
CHLORAMINES
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIQUID COLUMN CHROMATOGRAPHY
MELANIN
MELANOMAS
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PIGMENTS
RADIOISOTOPES
RADIORECEPTOR ASSAY
RECEPTORS
SEPARATION PROCESSES
SYNTHESIS
TRACER TECHNIQUES