Real-time PCR (a) and Western blot analysis (b) of the total uterine homogenate; representative image of Western blots (c) of NHE4 in steroid replaced ovariectomized rats and in rats at different phases of the oestrous cycle. Results indicate that NHE4 mRNA and protein expression were increased following E treatment and at Ps and Es stages of the oestrous cycle. NHE4 is the most abundant NHE isoform expressed in the uterus under E influence. Control: peanut oil, 0.2E: 0.2 μg 17β-oestradiol, 2E: 2 μg 17β-oestradiol, 20E: 20 μg 17β-oestradiol, 50E: 50 μg 17β-oestradiol, P: progesterone, E + P: 0.2 μg 17β-oestradiol + progesterone. Ps: proestrus, Es: estrus, Ms: metestrus, Ds: diestrus.: *P < 0.05, **P < 0.01, ***P < 0.001. n = 6 rats per group.