Effect of Calcium Status,Mass of Calcium Administered and Age on Ca 45 Metabolism in the Rat

Summary

(1) The fecal excretion of orally administered Ca⁴⁵ is a sensitive indication of the calcium status of the rat; (2) placing normal rats on a low calcium diet for as little as 2 days greatly increased their ability to absorb Ca⁴⁵ from the tract; (3) the specific activity of labeled calcium at the site of absorption had little effect upon its absorption; (4) in general, younger rats absorbed more Ca⁴⁵ than did older ones although there was no significant difference between 6 1/2 and 16-month-old animals; (5) for meaningful studies of this type, interpretations must include consideration of exchange reactions, and care must be given to initial selection of diets and animals, preparation of animals for the experiment, and dietary management during the experimental period.