Leucine and arginine enhance milk fat and milk protein synthesis via the CaSR/G i /mTORC1 and CaSR/G q /mTORC1 pathways.

We found that the G-protein-coupled receptor CaSR is an important amino acid sensor in mammary epithelial cells. Leucine and arginine promote milk synthesis partially through the CaSR/G/mTORC1 and CaSR/G/mTORC1 signaling systems in mammary gland epithelial cells. Although this mechanism needs further verification, it is foreseeable that this mechanism may provide new insights into the regulation of milk synthesis.