Role of intestinal calcium absorption in plasma calcium regulation of the rat.
Transmural calcium movement in the intestine involves both saturable and nonsaturable components, with the saturable movement subject to regulation by vitamin D and indirectly by parathyroid hormone. Under conditions of high-calcium intake, calcium absorption due to the saturable component is minimized and the numerical value of the nonsaturable component can equal that found in vitamin D-deficient or parathyroidectomized (PTX) animals on similar calcium intakes. Yet in PTX animals intestinal calcium represents a larger proportion of the calcium inflow into the central pool, and PTX animals are less able to regulate their plasma calcium than hormonally intact animals. This demonstrates that intestinal calcium input in the rat can be classified as a signal disturbing (raising) the plasma calcium.
D000042:Absorption; D000818:Animals; D002118:Calcium / Q000097:blood / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008433:Mathematics; D010280:Parathyroid Glands / Q000502:physiology; D051381:Rats / Q000378:metabolism*; D014807:Vitamin D / Q000502:physiology
D014807:Vitamin D; D002118:Calcium