Department of Nutrition, Dietetics, and Food Sciences, Utah State University, Logan, Utah 84322, USA.
Endocrinology. 2012 Apr;153(4):1609-15. doi: 10.1210/en.2011-1850. Epub 2012 Feb 14.
We have crossed ERp57(flx/flx) mice with commercially available mice expressing villin-driven cre-recombinase. Enterocytes isolated from 3- to 4-wk-old littermate (LM) male mice responded to 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃] with enhanced phosphate uptake relative to corresponding controls within 1 min of addition, whereas in cells from targeted knockout (KO) mice, the response was severely blunted. Unlike chick enterocytes, mouse enterocytes did not respond to phorbol ester with enhanced phosphate uptake. However, forskolin, which does not stimulate phosphate uptake in chick intestinal cells, did so in enterocytes isolated from either young male LM or KO mice. Intestinal cells isolated from young female LM mice also responded to 1,25(OH)₂D₃ with enhanced phosphate uptake within 5 min of hormone addition, whereas cells from KO mice did not. Forskolin also stimulated phosphate uptake in enterocytes from young female KO or LM mice. As with intestinal cells from adult male chickens or rats, cells from adult (8 wk) male LM mice lost the ability to respond to 1,25(OH)₂D₃) with enhanced phosphate uptake. In contrast, intestinal cells from adult female LM mice did respond with enhanced phosphate uptake within 1 min of steroid hormone addition relative to corresponding controls, and the magnitude of the effect was greater than that observed in enterocytes of young females. Cells isolated from young or adult male or female LM mice failed to respond to 1,25(OH)₂D₃ with enhanced protein kinase C activity. Finally, we have previously reported that mouse enterocytes have cell surface vitamin D receptor; however preincubation of such cells with anti-vitamin D receptor antibodies demonstrated that the classical receptor is not involved in the rapid 1,25(OH)₂D₃-stimulated uptake of phosphate.
我们将 ERp57(flx/flx) 小鼠与表达绒毛蛋白驱动的 cre 重组酶的商业可得的小鼠进行杂交。从 3 至 4 周龄同窝（LM）雄性小鼠中分离出的肠细胞在添加 1,25-二羟维生素 D₃ [1,25(OH)₂D₃] 后 1 分钟内，与相应的对照相比，对磷酸盐的摄取增加，而在靶向敲除（KO）小鼠的细胞中，这种反应严重减弱。与鸡肠细胞不同，鼠肠细胞对佛波醇酯没有增强的磷酸盐摄取反应。然而，在年轻雄性 LM 或 KO 小鼠的肠细胞中，forskolin（一种不能刺激鸡肠细胞磷酸盐摄取的物质）却能做到这一点。从小龄雌性 LM 小鼠中分离出的肠细胞也能在 5 分钟内对 1,25(OH)₂D₃ 做出反应，增加磷酸盐的摄取，而 KO 小鼠的细胞则没有。forskolin 也刺激了年轻雌性 KO 或 LM 小鼠的肠细胞中的磷酸盐摄取。与成年雄性鸡或大鼠的肠细胞一样，来自成年（8 周龄）雄性 LM 小鼠的细胞失去了对 1,25(OH)₂D₃ 增强的磷酸盐摄取的反应能力。相比之下，成年雌性 LM 小鼠的肠细胞在类固醇激素添加后 1 分钟内对磷酸盐的摄取有明显增加，且其作用的幅度大于年轻雌性肠细胞。从小龄或成年雄性或雌性 LM 小鼠中分离出的细胞对 1,25(OH)₂D₃ 没有增强蛋白激酶 C 活性的反应。最后，我们之前曾报道过，鼠肠细胞有细胞表面维生素 D 受体；然而，预先用抗维生素 D 受体抗体孵育这些细胞表明，经典受体不参与快速 1,25(OH)₂D₃ 刺激的磷酸盐摄取。
