Detection in Human Serum by Radioimmunoassay of Histidyl-Proline Diketopiperazine, a Metabolite of Thyrotropin-Releasing Hormone

Yoshiyuki Takahara, Fiorenzo Battaini, Douglas D. Ross, Steven A. Akman, Nicholas R. Bachur, Kent R Bailey, Edward Lakatos, Alan Peterkofsky

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Cyclo(His-Pro) is believed to be a metabolite of TRH. A specific antiserum directed against cyclo(His-Pro) was used to detect immunoreactive material in human serum. Gel filtration column chromatography was used to establish that cyclo(His-Pro)-like immunoreactivity was found not only in a free form established to be identical to cyclo(His-Pro) by high pressure liquid chromatography analysis on reverse phase and cation exchange columns, but also in a fraction of about 100, 000 mol wt. Free cyclo(His-Pro) was released by heating column fractions of 70, 000 mol wt that were not immunoreactive before heating. A procedure for estimation of the content of free cyclo(His-Pro) in human serum was developed. Normal levels of cyclo(His-Pro) determined by this procedure were in the range of 11–33 pmol/ml. The level of cyclo(His-Pro) in sera of individuals with hypothyroidism, hyperthyroidism, or alcoholic cirrhosis was in the normal range, while patients with renal failure had approximately 3-fold elevated levels of the peptide. Analysis of human sera drawn at 3-h intervals over a 24-h period suggested a circadian rhythm of cyclo(His-Pro) levels.

Original languageEnglish (US)
Pages (from-to)312-319
Number of pages8
JournalJournal of Clinical Endocrinology and Metabolism
Volume56
Issue number2
DOIs
StatePublished - 1983
Externally publishedYes

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

Fingerprint Dive into the research topics of 'Detection in Human Serum by Radioimmunoassay of Histidyl-Proline Diketopiperazine, a Metabolite of Thyrotropin-Releasing Hormone'. Together they form a unique fingerprint.

  • Cite this