Neuropeptide K-(1-24)-peptide: storage and release by carcinoid tumors.

Abstract

An antiserum directed against the COOH-terminal region of neuropeptide K-(1-24)-peptide that shows only 0.5% reactivity with neuropeptide K has been used in radioimmunoassay to study the posttranslation processing of human beta-preprotachykinin. A primary midgut carcinoid tumor contained high concentration of substance P (2970 pmol/g), neurokinin A (3660 pmol/g) and neuropeptide K-(1-24)-peptide (3430 pmol/g) but only a very low concentration (less than 5 pmol/g) of intact neuropeptide K. Neuropeptide K-(1-24)-peptide was also detected in extracts of metastatic tumor tissue from four patients with midgut carcinoid tumors. The amino acid sequence of tumor neuropeptide K-(1-24)-peptide was identical to that predicted from the nucleotide sequence of a human beta-preprotachykinin cDNA. The fasting plasma concentration of neuropeptide K-(1-24)-peptide was elevated in a patient with the carcinoid syndrome (821 fmol/ml compared with less than 18 fmol/ml in healthy subjects) and rose approximately 2-fold after intravenous pentagastrin. The study has demonstrated that the Lys25-Arg26 bond in neuropeptide K (corresponding to Lys96-Arg97 in the precursor) is an important processing site in human beta-preprotachykinin.

• Authors: J M Conlon, C F Deacon, L Grimelius, B Cedermark, R F Murphy, L Thim, W Creutzfeldt
• Journal: Peptides (Peptides) 1988 Jul-Aug Vol. 9 Issue 4 Pg. 859-66 ISSN: 0196-9781 [Print] United States
• PMID: 3226960 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Neuropeptides
• Peptide Fragments
• Tachykinins
• neuropeptide K
• Pentagastrin

Topics

• Aged
• Amino Acid Sequence
• Carcinoid Tumor (metabolism)
• Female
• Humans
• Middle Aged
• Molecular Sequence Data
• Neuropeptides (blood, metabolism)
• Pentagastrin (pharmacology)
• Peptide Fragments (blood, metabolism)
• Radioimmunoassay
• Tachykinins