Activation of calcium-sensing receptor by allosteric agonists cinacalcet and AC-265347 abolishes the 1,25(OH)D-induced Ca transport: Evidence that explains how the intestine prevents excessive Ca absorption.

Long-term high-calcium intake and intestinal calcium hyperabsorption are hazardous to the body. It is hypothesized that enterocytes possess mechanisms for preventing superfluous calcium absorption, including secretion of negative regulators of calcium absorption and utilization of calcium-sensing receptor (CaSR) to detect luminal calcium. Herein, Caco-2 monolayers were treated with high doses of 1,25(OH)D to induce calcium hyperabsorption or directly exposed to high apical calcium.

Intestinal mucosal changes and upregulated calcium transporter and FGF-23 expression during lactation: Contribution of lactogenic hormone prolactin.

As the principal lactogenic hormone, prolactin (PRL) not only induces lactogenesis but also enhances intestinal calcium absorption to supply calcium for milk production. How the intestinal epithelium res-ponses to PRL is poorly understood, but it is hypothesized to increase mucosal absorptive surface area and calcium transporter expression. Herein, lactating rats were found to have greater duodenal, jejunal and ileal villous heights as well as cecal crypt depths than age-matched nulliparous rats.