| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4325459 | Brain Research | 2012 | 5 Pages |
Melatonin is suggested to have effects on hypothalamic–pituitary–gonadal (HPG) axis. The pulsatile pattern of GnRH release, which results in the intermittent release of gonadotropic hormones from the pituitary, has a critical importance for reproductive function but the factors responsible from this release pattern are not known. Calcium is a second messenger involved in hormone release. Therefore, investigation of the effects of melatonin on intracellular free calcium levels ([Ca2+]i) would provide critical information on hormone release in immortalized GnRH neurons. The pattern of melatonin-induced intracellular calcium signaling was investigated by fluorescence calcium imaging using the immortalized GnRH-secreting GT1–7 hypothalamic neurons. Melatonin caused a significant increase in [Ca2+]i, which was greatly blocked by luzindole, a melatonin antagonist, or attenuated by pre-treatment with protein kinase C inhibitor. This study suggests that melatonin seems to have a direct effect on GnRH neurons.
► Melatonin increases intracellular calcium levels in GT1–7 cell lines by PKC mediated pathway. ► Melatonin action on intracellular calcium levels is mediated by melatonin receptors in the cell membrane. ► Melatonin causes a different pattern in calcium signaling, which may impair the pulsatile pattern of GnRH release.
