Hypervitaminosis A combined with calcium deficiency in rats.

Weanling male rats were fed for 24 days on a meat diet. Some received supplements of CaCO3, but others did not. For the final 14 days of the experiment some of the rats were given massive doses of retinol as retinyl acetate, but others were undosed. Some of the rats not given retinol had their food intakes paired with those given retinol. Skeletal examinations were made by radiography, and postmortem by measurement of the femur ash contents. The meat diet regularly reduced the femur ash to about half its normal level, but the CaCO3 supplements prevented any reduction. Skeletal fractures occurred consistently in all the rats given retinol, and with little if any difference in severity between the Ca-deficient and Ca-supplemented animals. Histological studies confirmed the accumulation of abnormal amounts of lipid round the liver Kupffer cells in hypervitaminosis A. Chemical estimations of liver fat gave higher values for the retinol-dosed animals than for their controls on paired food intakes. For control rats on unrestricted food intakes, however, higher values than for the retinol-dosed animals were found, but without lipid depositions round the Kupffer cells.