A novel signaling transduction pathway of melatonin on lactose synthesis in cows via melatonin receptor 1 (MT1) and prolactin receptor (PRLR).

In the current study, we explored the relationship between melatonin and lactose synthesis in and conditions. We found that long-term melatonin feeding to the dairy cows significantly reduced the milk lactose content in a dose dependent manner. This lactose reduction was not associated with a negative energy balance, since melatonin treatment did not alter the fat, glucose, or protein metabolisms of the cows.