Both PI3K/Akt and MAPkinase signaling pathways mediate the functions of mPRα in various cell models, including progestogen stimulation of sperm motility and oocyte maturation in fish [8,9], anti-apoptosis in fish ovarian follicle and human breast cancer cells [37,51,60], nitric oxide production in human umbilical vascular endothelial cells [48], and the progesterone-induced increase in sarcoplasmic reticulum calcium levels and decrease in myosin light chain (MLC) phosphorylation in human vascular smooth muscle cells resulting in their relaxation [50,63]. This evidence concerns the gene AKT1 and breast cancer.