A comparative study of the absorption of calcium and the availability of phytate-phosphorus in the golden hamster (Mesocricetus auratus) and the laboratory rat.

1. Balance studies were carried out with rats and golden hamsters (Mesocricetus auratus) given diets high and low in calcium (10.8 and 5.1-5.2 g Ca/kg respectively) and high and low in phytate (3.4 and 1.6 g phytate-phosphorus/kg respectively) in a 2 X 2 factorial experiment. 2. Values for Ca absorption and phytate availability (relative to the amount ingested) and for urinary excretion of Ca and P were significantly higher in the hamster than in the rat for all four diets. 3. Phytate availability was significantly greater on the low-Ca than on the high-Ca diets with both species. 4. Ca absorption was greater on the low-phytate than on the high-phytate diets but the differences were significant only for the hamster. 5. Absorption of both Ca and P was poorly controlled in the hamster compared to the rat.