Bone turnover in rats treated with 125dihydroxyv

Authors: Berit M Mortensen Kaare M Gautvik Jan O Gordeladze

Publish Date: 1993/02/01

Volume: 13, Issue: 1, Pages: 27-39

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Abstract

Female rats were given 125dihydroxyvitamin D3 125OH2D3 025 μg per 100 g body weight bw 25hydroxyvitamin D3 25OHD3 17 μg/100 g bw or 2425dihydroxyvitamin D3 2425OH2D3 17 μg/100 g bw subcutaneously three times a week for 12 weeks Traditional variables pertaining to calcium homeostasis and growth ie blood and urine calcium Ca and phosphate P serum levels of vitamin D3 metabolites parathyroid hormone PTH calcitonin CT prolactin PRL and growth hormone GH were measured every four weeks This data pool was correlated with bone matrix turnover parameters ie serum levels of alkaline phosphatase ALP and urinary hydroxyproline uHYP excretion After 12 weeks of treatment 125OH2D3 significantly enhanced serum total and ionized Ca urine Ca and urine P and also diminished urine cAMP due to reduced renal function creatinine clearance However 25OHD3 administration had no such impact 2425OH2D3 opposed the effect of 125OH2D3 after 12 weeks by significantly augmenting serum P and diminishing serum levels of total Ca and ionized Ca Cross sectional group analyses showed that criculating levels of ALP were directly related with serum 125OH2D3 and inversely related to serum 2425OH2D3 and CT Total uHYP and per cent nondialysable HYP ndHYP were reciprocally and positively correlated with serum PRL respectively However no such relations were observed with serum GHIt appears that rats with elevated circulating levels of 125OH2D3 exhibit increased bone resorption while augmented 2425OH2D3 is associated with the opposite Apparently high bone turnover ie reduced total urinary HYP and enhanced ndHYP is associated with high serum PRL

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