Niacin Stimulates Mammary Gland Development in Pubertal Mice through Activation of the AKT/mTOR and ERK1/2 Signaling Pathways
Previous studies have shown the effects of vitamins on the development of the mammary gland. However, the role of niacin in this process has not been reported. Therefore, the aim of this study was to investigate the effects of niacin on mammary gland development in pubertal mice and to use a mouse mammary epithelial cell line to study the underlying mechanism. The results showed that niacin could activate the AKT/mTOR and ERK signaling pathways by the Gi protein-coupled receptor and increase phosphorylation of 4EBP1 to promote the synthesis of cell proliferation markers, leading to the dissociation of the Rb-E2F1 complex in mMECs. In addition, 0.5% niacin promoted mammary duct development, increased the expression of cyclin D1/D3 and PCNA, and activated Akt/mTOR and ERK1/2 in the mammary glands of pubertal mice. These results strongly suggest that niacin stimulates mammary gland development in pubertal mice through the Akt/mTOR and ERK1/2 signaling pathways and that the Gi protein-coupled receptor is essential for this function.