Metabolic stability of long-acting luteinizing hormone-releasing hormone antagonists.
Long-acting luteinizing hormone-releasing hormone (LHRH) antagonists designed to be protease resistant consisted of a series of novel decapeptides structurally similar to LHRH. The aim of this study was to evaluate the in vitro metabolic stability of the LHRH decapeptides using pancreatin and homogenates models and identify the metabolites in rat liver homogenate for the purpose of illustrating the metabolic features of the decapeptides. The major metabolites in rat liver homogenate were identified by LC-ESI-MS(n). The half-lives of the 11 LHRH decapeptides were from 44 to 330 min in the pancreatin model. The half-lives of the five decapeptides in rat liver, kidney and lung homogenates were between 8 and 462 min. The most stable decapeptides were the LY616 and LY608 peptides with half-lives of 36 min in liver homogenate. Two major cleavage sites were found by analysing the metabolites of the LY618 peptide in rat liver homogenate, between the Pal(3)-Ser(4) and the Leu(7)-Ilys(8) peptide bonds. The major metabolites were produced via cleavages of peptide bonds at these sites, and further metabolic reactions such as hydroxylation, oxidative dechlorination, alcohol dehydration and isopropyl dealkylation were also observed.
Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing, 100069, China.
Jin-Feng
JF
Yao
Ning
N
Zhou
Yu-Jian
YJ
Lv
Ruifeng
R
Zhang
Ke-Liang
KL
Liu
Ming
M
Xue
D000595:Amino Acid Sequence; D000818:Animals; D002853:Chromatography, Liquid; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D006207:Half-Life; D007668:Kidney / Q000737:chemistry*; D008099:Liver / Q000737:chemistry*; D008168:Lung / Q000737:chemistry*; D008297:Male; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis*; D010194:Pancreatin / Q000737:chemistry; D055550:Protein Stability; D051381:Rats; D017207:Rats, Sprague-Dawley; D021241:Spectrometry, Mass, Electrospray Ionization; D014020:Tissue Extracts / Q000737:chemistry
D009842:Oligopeptides; D014020:Tissue Extracts; D007987:Gonadotropin-Releasing Hormone; D010194:Pancreatin