Figure 5.

Pup weight, milk protein concentration, and milk osmolality measured in lactating dams receiving a normal calcium diet or in calcium-restricted lactating mice treated with a calcimimetic or the control compound. (a) Average pup body weight on day 12 of lactation in litters suckling on dams fed a normal-calcium diet or a low-calcium diet with or without calcimimetic treatment. Mice received 40 μmol/kg/d of NPS S467 or one of two doses of NPS R467, 4 μmol/kg/d (low) or 40 μmol/kg/d (high). Pups were significantly smaller when mothers consumed a low-calcium diet. Calcimimetic treatment did not significantly increase pup weight. (b) Protein concentration of milk derived from the groups of mice described in a. Each bar represents the mean of three to nine samples; error bars represent the SEM. Milk protein was significantly higher in samples from mice on a low-calcium diet compared with mice on a normal-calcium diet (P < 0.001) or mice receiving NPS R467 (P < 0.01). However, the protein concentrations were not significantly different in milk from mice receiving NPS R467 compared with milk from those on a normal diet. (c) Milk osmolality in samples from the same groups described in a and b. Osmolality was significantly increased in milk from calcium-restricted mice (P < 0.001 vs. normal Ca) and mice receiving NPS S467 (P < 0.01 vs. normal Ca). The low dose of NPS R467 did not significantly decrease milk osmolality, but the high dose did (P < 0.001 for low Ca vs. low Ca plus high R467). mOsm, milliosmoles.