Evidence for implication of tryptophan hydroxylase in the regulation of melatonin synthesis in ovine pinealocytes in culture.
1. Tryptophan hydroxylase (TPOH) is the first enzyme in the melatonin synthesis pathway and the rate-limiting enzyme in serotonin synthesis. We established in this study an in vitro model of ovine pinealocytes to investigate the role of TPOH in melatonin production. 2. We demonstrated that TPOH is highly expressed both in vivo and in vitro at the protein and mRNA levels. In vitro pinealocytes show ultrastructural features similar to those previously described in vivo. 3. Moreover, our in vitro model allowed us to study the regulation mechanisms for melatonin synthesis in sheep pinealocytes and to demonstrate that both transcriptional and posttranscriptional mechanisms are involved. 4. In particular, our results suggest that TPOH plays an essential role in the regulation of melatonin synthesis.
Privat
Karen
K
INSERM U433, Faculté de Médecine RTH Laennec, Rue Guillaume Paradin, 69372 Lyon 08, France.
Brisson
Christine
C
Jouvet
Anne
A
Chesneau
Didier
D
Ravault
Jean-Paul
JP
Fevre-Montange
Michelle
M
D000818:Animals; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000502:physiology; D008297:Male; D008550:Melatonin / Q000032:analysis / Q000096:biosynthesis*; D010870:Pineal Gland / Q000378:metabolism* / Q000648:ultrastructure; D012756:Sheep; D014365:Tryptophan Hydroxylase / Q000032:analysis / Q000096:biosynthesis*
D014365:Tryptophan Hydroxylase; D008550:Melatonin