Calcium balance in laboratory rabbits.

Abstract

Calcium balance was measured and the renal handling of calcium was investigated in female New Zealand White rabbits. The rabbits were studied in metabolism cages while they were consuming tap water and a laboratory feed. The rabbits were growing and were in positive calcium balance. Of the excreted calcium 47 +/- 3% (mean +/- SD) was in the urine and 53 +/- 3% was in the feces. The mean plasma total calcium concentration was 3.32 +/- 0.09 mM, of which the ultrafiltrable fraction was 0.679. The percentage of calcium filtered at the glomeruli that was excreted in the urine was 44.9 +/- 0.9%. We conclude that under standard laboratory conditions these rabbits have higher plasma calcium concentrations and urinary fractional excretions of calcium than other mammalian species.