The effect of aminoacetonitrile on calcium metabolism and bone in the rat.

1. The effect of the osteolathyrogen aminoacetonitrile (AAN) on plasma calcium, phosphate and alkaline phosphatase, on bone, on growth rates, on absorption of calcium and phosphate in the gut and on their urinary excretion, has been examined in rats. 2. AAN caused a general deterioration in the health of the rat and reduced its rate of growth. 3. AAN reduced plasma calcium and increased plasma alkaline phosphatase but did not affect plasma phosphate. 4. AAN caused obvious deformity of the long bones with large exostoses. The femurs of the lathyritic rats had an increased fat-free weight and increased fat-free weight to ash weight ratio. 5. AAN increased true and apparent absorption of calcium but did not consistently affect urinary excretion of phosphate or apparent absorption of phosphate. 6. AAN did not produce a significant reduction in the plasma calcium of parathyroidectomized or thyroparathyroidectomized rats. 7. Absorption of calcium from ligated jejunal loops was increased in AAN-treated parathyroidectomized rats. 8. In some experiments parathyroidectomy or thyroparathyroidectomy protected the bones from the effect of AAN.