Régulation de l’absorption intestinale du calcium chez le chamelon (<em>Camelus dromedarius</em>)

Postprandial hypercalcemia and hyperphosphatemia, as well as intestinal calcium (Ca) absorption were measured in 12 newborn camels. They were divided into four groups of three animals. Groups 1 and 2 received an i.v. infusion of synthetic human parathyroid hormone (PTH)/PTH-related peptide (PTHrP) or solvent alone, respectively. At the beginning of infusion, groups 1 and 2 received an oral administration of artificial milk. Groups 3 and 4 received i.v. injections of 1α,25-dihydroxyvitamin D 3 (1α,25(OH) 2 D 3 ) or of solvent, respectively. At the last injection, groups 3 and 4 received an oral administration of SrCl 2 . PTHrP induced a significant rise in postprandial hypercalcemia and hyperphosphatemia. It had no significant effect on urinary volume or on Ca renal excretion, but it increased phosphorus (P) renal excretion. 1α,25(OH) 2 D 3 induced a significant increase in plasma levels of strontium, Ca and P. 1α,25(OH) 2 D 3 did not induce significant variations on the urinary volume nor on Ca, P, or Sr renal excretion. These results seem to show that PTHrP and 1α,25(OH) 2 D 3 play a major role in bone growth of camel calves.