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Updated: May 1, 2026

In Situ Ca2+ Imaging of the Enteric Nervous System
Published on: January 29, 2015
Glucose 1-phosphate increases active transport of calcium in intestine
Hidetake Fujinaka1, Junji Nakamura, Hisataka Kobayashi
1Biological Science Laboratories, Kao Corporation, 2606 Akabane, Ichikaimachi, Haga, Tochigi 321-3497, Japan.
Abstract:
Active calcium transport in intestine is essential for serum calcium homeostasis as well as for bone formation. It is well recognized that vitamin D is a major, if not sole, stimulator of intestinal calcium transport activity in mammals. Besides vitamin D, endogenous glucose 1-phosphate (G1P) affects calcium transport activity in some microorganisms. In this study, we investigated whether G1P affects intestinal calcium transport activity in mammals as well. Of several glycolytic intermediates, G1P was the sole sugar compound in stimulating intestinal calcium uptake in Caco-2 cells. G1P stimulated net calcium influx and expression of calbindin D9K protein in rat intestine, through an active transport mechanism. Calcium uptake in G1P-supplemented rats was greater than that in the control rats fed a diet containing adequate vitamin D3. Bone mineral density (BMD) of aged rat femoral metaphysis and diaphysis was also increased by feeding the G1P diet. G1P did not affect serum levels of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] at all. These results suggest that exogenously applied G1P stimulates active transport of calcium in intestine, independent of vitamin D, leading to an increase of BMD.
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