Radioimmunoassay for an analog of thyrotrophin-releasing hormone, γ-butyrolactone-γ-carbonyl-l-histidyl-l-prolinamide (DN-1417)

K. Shiota, A. Miyake, C. Tsunoda, Y. Oka, Y. Nagawa, R. Nakayama

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A heterologous radioimmunoassay method was established to determine plasma levels of γ-butyrolactone-γ-carbonyl-L-histidyl-L-prolinamide (DN-1417). As this compound is unstable in the incubation buffer, we introduced a conversion step. DN-1417 in the plasma was extracted with a solution of isopropanol-isobutylamine (4 : 1) and incubation was performed at room temperature for 2 h for the conversion of DN-1417 into N-[2-hydroxy-4-(isobutylcarbamoyl)butyryl]-L-histidyl-L-prolinamide (DN-isobutylamide). 125I-labeled 2-hydroxy-4-carboxybutyryl-L-histidyl-L-prolinamide and antisera, which was raised in the rabbit using an esterified derivative of DN-1417 conjugated with BSA as an antigen, were used for a sensitive radioimmunoassay of DN-isobutylamide. In this system, 0.2 ng DN-isobutylamide/ml plasma, equivalent to 0.16 ng DN-1417/ml, was detected and there was no apparent interference from its metabolites. The within-assay coefficients of variation were 7.6% at 7.73 ng/tube and 13.7% at 1.32 ng/tube. The between-assay coefficients of variation were 16.1% at 6.43 ng/tube and 12.2% at 1.20 ng/tube. The mean recovery rate of the assay system was 76.0 ± 3.2% (S.E.M.).

Original languageEnglish
Pages (from-to)69-80
Number of pages12
JournalJournal of Immunological Methods
Volume51
Issue number1
DOIs
Publication statusPublished - 1982 May 28
Externally publishedYes

Keywords

  • DN-1417
  • radioimmunoassay
  • TRH analogs
  • γ-butyrolactone-γ-carbonyl-L-histidyl-L-prolinamide

ASJC Scopus subject areas

  • Biotechnology
  • Immunology

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