Characterization of human melatonin synthesis using autoptic pineal tissue

Katrin Ackermann, Roman Bux, Udo Rüb, Horst-Werner Korf, Gerold Kauert, Jörg H Stehle

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

The mammalian pineal gland synthesizes rhythmically the hormone melatonin, which provides the body with a signal coding the duration of the night period. The ultimate enzymatic step in melatonin synthesis is achieved by the hydroxyindole O-methyltransferase (HIOMT); the rate-limiting enzyme is, however, the arylalkylamine N-acetyltransferase (AA-NAT). In contrast to the central importance of a transcriptional regulation of the Aa-nat gene for rodent melatonin synthesis, mechanisms in the human pineal gland are elusive. Therefore, pineal tissue, taken from regular autopsies (n = 69; postmortem intervals ranging from 9 to 147 h) was analyzed simultaneously for Aa-nat and Hiomt mRNA levels by PCR, AA-NAT activity using (14)C-acetyl-coenzyme A, HIOMT activity using S-adenosyl-l-[(14)C]-methionine, and melatonin content using an ELISA. Results were allocated to asserted time-of-death groups (day, 1,000 to 1,630 h; dusk, 1,630 to 2,200 h; night, 2,200 to 0730 h; dawn, 0730 to 1,000 h). RNA degradation rates of genes of interest ran in parallel, and, therefore, data normalization could be established, regardless of postmortem delay in tissue sampling. Aa-nat and Hiomt mRNA and HIOMT activity showed no diurnal rhythm. In contrast, a significant rhythm was found for the correlation between time of death and both AA-NAT activity and melatonin content, with elevated values during dusk and night. Presented data demonstrate that postmortem brain tissue can be used to detect the remnant of premortem adaptive changes in neuronal activity. In particular, our results give strong experimental support for the idea that transcriptional mechanisms are not dominant for the generation of rhythmic melatonin synthesis in the human pineal gland.

Original languageEnglish
Pages (from-to)3235-42
Number of pages8
JournalEndocrinology
Volume147
Issue number7
DOIs
Publication statusPublished - Jul 2006

Keywords

  • Acetylserotonin O-Methyltransferase
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Arylalkylamine N-Acetyltransferase
  • Autopsy
  • Biological Clocks
  • Brain
  • Child
  • Female
  • Humans
  • Male
  • Melatonin
  • Middle Aged
  • Pineal Gland
  • Journal Article
  • Research Support, Non-U.S. Gov't

Fingerprint

Dive into the research topics of 'Characterization of human melatonin synthesis using autoptic pineal tissue'. Together they form a unique fingerprint.

Cite this