Objective To investigate the mechanism of bone lead mobilization in mice during gestation and lactation.
Methods A group of 36 female Kunming mice were exposed to lead acetate in drinking water (10.0 mol/L, pure lead) for 4 weeks before pregnancy. At gestational day (GD) 1, 2 and 14, and lactational day (LD) 1, 10 and 21, levels of lead in blood and femur and levels of parathyroid hormone (PTH) in serum were measured by graphite furnace atomic absorption spectrometry and radioimmunoassay, respectively, and compared with the controls at the same time spots.
Results In lead-treated mice, the le vels of blood lead (PbB) and PTH were increased, and the levels of blood calcium (CaB), femur calcium (CaF) and femur lead (PbF) were decreased during the second half of gestation. At the end of lactation, the levels of PbB were significantly increased to (0.38& #177;0.02)μmol/L, up by 65.22%; the levels of PbF were significantly decreased to (269.14& #177;9.78)nmol/g, down by 28.45%; the le vels of CaB and CaF were significantly decreased to (1.85& #177;0.07)mmol/L and (12.74& #177;0.38)mmol/g, down by 18.50% and 17.75% respectively, compared with that on GD1 (P<0.05). The serum PTH were significantly increased to (6.04& #177;0.50)μg/L on GD14, up by 103.37% compared with that on GD1 (P<0.05) and maintained in a high level until LD 21. There were significant differences of PbB, PbF, CaB, CaF and PTH between the exposures and the controls in all stages of experiment (P<0.05). Moreover, there was a positive correlation between the PbB and the serum PTH levels in dams with lead exposure (r=0.790, P<0.000 1).
Conclusion The elevated serum PTH levels might be involved in maternal bone lead mobilization during gestation and lactation.
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