Pineal melatonin synthesis and release are not altered throughout the estrous cycle in female rats.
Melatonin times reproduction with seasons in many photoperiodic mammalian species. Whether sexual hormones reflect on melatonin synthesis is still debated. The aim of this work was to study, using a large panel of technical approaches, whether the daily profile of pineal melatonin synthesis and release varies with the estrous cycle in the female rat. The mRNA levels and enzyme activities of the melatonin synthesizing enzymes, arylalkylamine N-acetyltransferase and hydroxyindole-O-methyltransferase were similar at the four stages of the rat estrous cycle. The endogenous release of melatonin, followed by transpineal microdialysis during six consecutive days in cycling female rats, displayed no significant variation during this interval. Taken together, the present results demonstrate that there is no regular fluctuation in the pineal metabolism leading to melatonin synthesis and release throughout the estrous cycle in female rats.
Skorupa
Ana-Lucia
AL
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Garidou
Marie-Laure
ML
Bothorel
Béatrice
B
Saboureau
Michel
M
Pévet
Paul
P
Neto
José Cipolla
JC
Simonneaux
Valérie
V
D000121:Acetylserotonin O-Methyltransferase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology; D030762:Estrous Cycle / Q000378:metabolism*; D005260:Female; D008550:Melatonin / Q000096:biosynthesis* / Q000378:metabolism; D010870:Pineal Gland / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D011506:Proteins; D000121:Acetylserotonin O-Methyltransferase; D001191:Arylamine N-Acetyltransferase; D008550:Melatonin