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Reversal of the EHDP Inhibition of Calcium Absorption by 1,25‐Dihydroxycholecalciferol
Author(s) -
Bonjour J.P.,
DeLuca H. F.,
Fleisch H.,
Trechsel U.,
Matejowec L. A.,
Omdahl J. L.
Publication year - 1973
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1973.tb00328.x
Subject(s) - hypercalcaemia , endocrinology , medicine , calcium , cholecalciferol , vitamin d and neurology , absorption (acoustics) , calcium metabolism , chemistry , vitamin , materials science , composite material
. Disodium ethane‐ 1 ‐hydroxy ‐ 1,1 ‐diphosphonate (EHDP), given a t a dose of 10 mg of P kg ‐1 day ‐1 S.C. for 7 days to rats on a high calcium‐high vitamin D diet, inhibits bone mineralisation, induces hypercalcaemia and decreases the intestinal calcium absorption. The intestinal response could be explained by an interference with vitamin D metabolism. To test this hypothesis, cholecalciferol (D,), 25‐hydroxy‐cholecnlciferol (25‐OHD 3 ) and 1,25‐dihydrorycholecalciferol [1,25‐(OH) 2 D 3 ] were administered to EHDP‐treated rats. A single injection of 325 pmoles of 1,25‐(OH) 2 D 3 completely reversed the EHDP‐induced decrease in intestinal calcium absorption. No effect was observed when the same dose or a tenfold greater dose (3250 pmoles) of D 2 or 25‐OHD 3 were administered or when these two compounds were given a t the dose of 6350 pmoles/day during the 7 days of EHDP treatment. These findings strongly suggest that the low calcium absorption rate observed in the EHDP‐treated rats is due to a reduced conversion of 25‐OHD 3 to 1,25‐(OH) 2 D 3 . The role of the EHDP‐induced hypercalcaemia to account for this response remains to be established.