The in vitro effects of melatonin and Cry gene on the secretion of estradiol from camel ovarian granulosa cells.

Bactrian camel as endemic economic species to the Northwest of China, its seasonal reproduction severely limits litter rates. In addition to melatonin, seasonal reproduction of animals is also regulated by the biological clock, but the specific molecular mechanism is not clear. To investigate the effects of melatonin and Cryptochrome (Cry) genes on seasonal reproduction, they were placed in ovarian granulosa cells, and their effects on reproduction were determined by measuring the concentrations of estradiol. Immunohistochemistry revealed that melatonin receptor protein (MT) was expressed in the cytosol and membrane of the ovarian granulosa cells, and the highest levels of CRY were expressed in the nuclei. The concentrations of estradiol in the cell culture supernatant were increased after the addition of exogenous melatonin or overexpression of MT, but these were decreased after MT was over expressed, and exogenous melatonin was added to the cells. In addition, there was a significant increase in the concentrations of estradiol after the Cry genes were overexpressed; however, the estradiol concentrations were decreased after the Cry genes were silenced. Our findings demonstrate that the MT and Cry genes play important roles in ovarian granulosa cell production of estradiol in a seasonally breeding species.