| Autor: |
Garcia RA; University of São Paulo, Institute of Biomedical Sciences, Department of Physiology and Biophysics, Av. Prof. Lineu Prestes 1524, 1st floor, room 118, Sao Paulo, SP, CEP 05508-900, Brazil., Afeche SC, Scialfa JH, do Amaral FG, dos Santos SH, Lima FB, Young ME, Cipolla-Neto J |
| Jazyk: |
angličtina |
| Zdroj: |
Life sciences [Life Sci] 2008 Jan 02; Vol. 82 (1-2), pp. 108-14. Date of Electronic Publication: 2007 Nov 01. |
| DOI: |
10.1016/j.lfs.2007.10.016 |
| Abstrakt: |
The mammalian pineal gland synthesizes melatonin in a circadian manner, peaking during the dark phase. This synthesis is primarily regulated by sympathetic innervations via noradrenergic fibers, but is also modulated by many peptidergic and hormonal systems. A growing number of studies reveal a complex role for melatonin in influencing various physiological processes, including modulation of insulin secretion and action. In contrast, a role for insulin as a modulator of melatonin synthesis has not been investigated previously. The aim of the current study was to determine whether insulin modulates norepinephrine (NE)-mediated melatonin synthesis. The results demonstrate that insulin (10(- 8)M) potentiated norepinephrine-mediated melatonin synthesis and tryptophan hydroxylase (TPOH) activity in ex vivo incubated pineal glands. When ex vivo incubated pineal glands were synchronized (12h NE-stimulation, followed by 12h incubation in the absence of NE), insulin potentiated NE-mediated melatonin synthesis and arylalkylamine-N-acetyltransferase (AANAT) activity. Insulin did not affect the activity of hydroxyindole-O-methyltranferase (HIOMT), nor the gene expression of tpoh, aanat, or hiomt, under any of the conditions investigated. We conclude that insulin potentiates NE-mediated melatonin synthesis in cultured rat pineal gland, potentially through post-transcriptional events. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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