Melatonin Receptor Mel1b ‐ and Mel1c‐mediated Green Light Induced the Secretion of Growth Hormone in Anterior Pituitary of Chicks

Monochromatic green light promotes the secretion of plasma melatonin. Melatonin influences the expression of Pit ‐1 and the secretion of growth hormone in the adenohypophysis cells through melatonin receptor Mel1b and Mel1c. AbstractPrevious studies have found that melatonin was related to the growth and development in avian. Therefore, the newly hatched broilers were exposed to colors of light to establish a model of pinealectomy and explored the mechanism of pineal melatonin promoting growth hormone (GH) secretion. The results showed that green light (GL) promoted the levels  of GH, pituitary‐specific transcription factor‐1 (Pit‐1) genes and proteins in pituitary. Moreover, the mRNA and protein levels of melatonin receptor subtypes Mel1b and Mel1c in the pituitary in GL were higher than other monochromatic light groups. After pinealectomy, the expression of Pit‐ 1, GH, Mel1b and Mel1c in pituitary decreased.In vitro, exogenous melatonin promoted the level ofPit ‐1 mRNA and the secretion of GH in anterior pituitary cells. However, when melatonin was added with exogenous selective Mel1b antagonist (4 ‐phenyl‐2‐propionamideotetralin) and selective Mel1c antagonist (prazosin), the level ofPit ‐1 mRNA and the GH secretion decreased. When selective Mel1b and Mel1c antagonists were added simultaneously, the decrease inPit ‐1 mRNA and GH secretion was more significant. These results indicated that pineal melatonin promotes the expression of Pit ‐1 under G...
Source: Photochemistry and Photobiology - Category: Science Authors: Tags: Research Article Source Type: research