Two indoleamines are secreted from rat pineal gland at night and act on melatonin receptors but are not night hormones
| Autor: | Bo Hyun Lee, Bertil Hille, Ivana L. Bussi, Chris Hague, Horacio O. de la Iglesia, Duk Su Koh |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Male
0301 basic medicine Serotonin endocrine system medicine.medical_specialty medicine.medical_treatment Pinealectomy Pineal Gland Melatonin receptor Article Rats Sprague-Dawley Melatonin 03 medical and health sciences chemistry.chemical_compound Pineal gland 0302 clinical medicine Endocrinology N-Acetylserotonin Internal medicine medicine Animals Humans Circadian rhythm Receptor Receptor Melatonin MT2 Receptor Melatonin MT1 Tryptamines Circadian Rhythm Rats HEK293 Cells 030104 developmental biology medicine.anatomical_structure chemistry hormones hormone substitutes and hormone antagonists 030217 neurology & neurosurgery medicine.drug Hormone |
| Zdroj: | J Pineal Res |
| ISSN: | 1600-079X 0742-3098 |
| Popis: | INTRODUCTION: At night, the pineal gland produces the indoleamines, melatonin, N-acetylserotonin (NAS), and N-acetyltryptamine (NAT). Melatonin is accepted as a hormone of night. Could NAS and NAT serve that role too? METHODS: Concentration-response measurements with overexpressed human melatonin receptors MT(1) and MT(2); mass spectrometry analysis of norepinephrine-stimulated secretions from isolated rat pineal glands; analysis of 24-hour periodic samples of rat blood. RESULTS: We show that NAT and NAS do activate melatonin receptors MT(1) and MT(2), although with lower potency than melatonin, and that in vitro, melatonin and NAS are secreted from stimulated, isolated pineal glands in roughly equimolar amounts, but secretion of NAT was much less. All three were found at roughly equal concentrations in blood during the night. However, during the day, serum melatonin fell to very low values creating a high-amplitude circadian rhythm that was absent after pinealectomy, whereas NAS and NAT showed only small or no circadian variation. CONCLUSION: Blood levels of NAS and NAT were insufficient to activate peripheral melatonin receptors and they were invariant, so they could not serve as circulating hormones of night. However, they could instead act in paracrine circadian fashion near the pineal gland or via other higher-affinity receptors. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text