Pineal melatonin deprivation alters the mRNA expression of melatonin and steroidogenic-related receptor genes in rat oviduct and uterus during the estrus stage of estrous cycle

The effects of pinealectomy and melatonin replacement therapy on the mRNA expression of melatonin (Mt1, Mt2 and Rora), steroidogenic (Era - Estrogen a, Erb - Estrogen b, Ar - Androgen, Pgr - Progesterone, Lhr - LH and Oxr - Oxytocin receptors) -related receptors and melatonin-synthetic enzyme genes (Tph1, Asmt and Aanat) in oviduct and uterus of Wistar rats were studied. Tissues were collected from sham-pinealectomized (Control), pinealectomized (Pinx) and Pinx plus melatonin- supplemented (Pinx-Mel) females during the estrus stage of both the light (ZT6) and dark (ZT18) phases of the light-dark cycle. In oviduct, Pinx altered the mRNA expression of Mt1, Mt2, Rora, Era, Pgr, Oxr, Asmt and Aanat genes. In uterus, Pinx altered the mRNA expression of Mt1, Mt2, Rora, Lhr, Pgr, Oxr and Tph1 genes. Melatonin treatment partially or completely restored the Mt2, Rora, Era, Oxr, Asmt and Aanat mRNA expressions in oviduct and the Mt1, Mt2 and Rora mRNA expressions in uterus. These alterations varied according to the phase of light-dark cycle. The results suggest that pineal melatonin regulates the daily mRNA expression of melatonin and steroidogenic-related receptors in the rat oviduct and uterus during the estrus stage of estrous cycle. Melatonin also regulates the daily mRNA expression of Asmt and Aanat in oviduct and Tph1 in uterus.