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Effect of Zn deficiency and subsequent Zn repletion on bone mineral composition and markers of bone tissue metabolism in 65 Zn‐labelled, young‐adult rats
Author(s) -
Windisch W.,
Wher U.,
Rambeck W.,
Erben R.
Publication year - 2002
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1046/j.1439-0396.2002.00377.x
Subject(s) - endocrinology , medicine , chemistry , bone remodeling , bone mineral , metabolism , composition (language) , urine , zoology , biology , osteoporosis , linguistics , philosophy
Summary The objective of the present study was to investigate the effect of changing skeletal Zn load (mobilization/restoring) on bone mineral composition and bone tissue metabolism. For this purpose, 36 65 Zn‐labelled, young‐adult female rats were fed with either a purified diet with sufficient Zn (21 μg/g, control) for 26 days, or deficient Zn (1.4 μg/g) for 12 days followed by 14 days repletion with the control diet. The animals were killed at the onset of the study (reference: n=4), at the end of the Zn deficiency episode (control: n=4; Zn deficiency: n=4), subgroups (n=4) of Zn repleted animals at repletion days 2, 4, 7, 10 and 14, and at day 14 the remaining controls also (n=4). Zn deficiency reduced skeletal Zn concentration from 198 to 155 μg/g of bone dry matter. About half of mobilized skeletal Zn was refilled within 2 days of repletion and was completely restored until the end of the study. Concentrations of bone ash, Ca, P and Mg remained constant (means in bone dry matter: 51% bone ash, 191 mg Ca/g, 95 mg P/g, 4.4 mg Mg/g). Blood plasma concentrations of osteocalcin and daily urinary excretions of pyridinoline PYD and dexoxypyridinoline DPD were unaffected by treatment (mean: 57 ng/ml, 222 nmol/day, 137 nmol/day). Also daily urinary excretions of Ca, P and Mg remained fairly constant (means: 0.26 mg/day, 16 mg/day, 1.5 mg/day). 65 Zn autoradiography of femur sections revealed a pronounced Zn exchange in the area of the metaphysis and epiphysis. We conclude that transient mobilization and restoration of skeletal Zn occurs mainly in trabecular bone, and does not involve major changes in bone mass, macro mineral content, or bone tissue turnover in young‐adult rats.