Identification of major urinary metabolites of nafarelin acetate, a potent agonist of luteinizing hormone-releasing hormone, in the rhesus monkey
Nafarelin acetate (less than Glu-His-Trp-Ser-Tyr-3-(2-naphthyl)-D-Ala-Leu-Arg-Pro-Gly-NH2) is a potent agonistic analogue of luteinizing hormone-releasing hormone. After a single iv administration of nafarelin acetate (with UC label at C-3 of 3-(2-naphthyl)-D-Ala) to female rhesus monkeys, about 80% of the radioactivity was eliminated in urine. Five major radioactive urinary metabolites were isolated and purified by reversed phase HPLC. Four of these metabolites, identified by amino acid analysis, were short peptides: the 5-10-hexapeptide amide, the 6-10-pentapeptide amide, the 5-7-tripeptide, and the 6-7-dipeptide. The fifth metabolite, which accounted for about 15% of the radioactivity administered, was shown by NMR and mass spectrometry to be 2-naphthylacetic acid. A possible pathway of its formation is by oxidative deamination of 3-(2-napthyl)-D-Ala to give the corresponding alpha-keto acid, followed by oxidative decarboxylation of the alpha-keto acid. These five metabolites together accounted for about 70% of the radioactivity recovered in the urine of rhesus monkeys, or more than half of the radioactivity in the administered dose. Nafarelin acetate was also present in small amounts. Several of these metabolites were also present in plasma of the rhesus monkey.
- Research Organization:
- Syntex Research, Palo Alto, CA
- OSTI ID:
- 6044531
- Journal Information:
- Drug Metab. Dispos.; (United States), Vol. 5
- Country of Publication:
- United States
- Language:
- English
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CARBON 14 COMPOUNDS
EXCRETION
PROTEINS
METABOLITES
ACETATES
AMINO ACIDS
LH-RH
LIQUID COLUMN CHROMATOGRAPHY
MONKEYS
URINE
ANIMALS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY FLUIDS
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CHROMATOGRAPHY
CLEARANCE
HORMONES
LABELLED COMPOUNDS
LIBERINS
MAMMALS
MATERIALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
PRIMATES
SEPARATION PROCESSES
VERTEBRATES
WASTES
550501* - Metabolism- Tracer Techniques