Effects of coumestrol administration to pregnant and lactating mice on intestinal alkaline phosphatase activity

The present study was conducted to clarify the effects of coumestrol administration on Ca metabolism during pregnancy and in lactating mice. From 6.5 to 16.5 days post coitus (dpc), pregnant mice were administered coumestrol at 200 µg/kg body weight/day. The duodenum, jejunum and blood samples were obtained at 17.5 dpc or 10 days after parturition (dap). Coumestrol administration decreased alkaline phosphatase (ALP) activity and mRNA expression of IAP and estrogen responsive genes, c-fos and vascular endothelial growth factor (VEGF), in the duodenum and jejunum of pre-delivery mice. In lactating mice, the ALP activity and mRNA expression of IAP were not changed, although coumestrol administration decreased mRNA expression of c-fos in the duodeum and VEGF in the jejunum. Coumestrol did not affect serum Ca and the expression of vitamin D receptor protein in the duodenum and jejunum. Thus, coumestrol administration during pregnancy may decrease the mRNA expression of IAP and the ALP activity in the intestine of the pre-delivery mice through ERα, but coumestrol had little effect on intestinal ALP activity at 10 days after parturition.