The effects of vitamin D-free diet with low Ca content on 24 hours' 99mTc-methylendiphosphonate retention (in the whole body and tibia), long-term the whole body 85Sr retention and 2 hours' 85Sr catchment in epiphysis, metaphysis and diaphysis of femur and tibia in rats (at the same time in certain experiments femur density and weight after incineration were established) were followed. The whole body 99mTc-MDP retention increases significantly as early as the third day of the diet administration, retention in tibia and the whole body is in further 2 experiments increased after 1, 2 and 4 weeks of the diet (density decreases from the first or the second week). The whole body 85Sr retention is significantly increased as early as after 2 days of the diet, the great difference against controls only slowly decreases after discontinuation of low-Ca diet. Further experiment followed 2 hours' 85Sr catchment in femur and tibia samples after 2, 5, 10 and 20 days of diet--catchment increase is significant after 20 days (bone density and ash weight is significantly decreased after 10 and 20 days of diet). Thus retention of both osteotrophic substances in bone is as a result of low Ca diet increased. This reaction is in case with 85Sr expected, in that of 99mTc-MDP it suggests a possible relation of the catchment and mineral component of osseous tissue. Increased retention of both the substances obviously fails to be related to local blood circulation which was in this situation in our previous experiments decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Laborator pro endokrinologii a metabolismus a 3 interní klinika fakulty vseobecného lékarství Univerzity Karlovy Praha