A comparison of amino acid-induced hypercalciuria in sham-operated and parathyroidectomized rats

In previous studies we have demonstrated that the reduced renal reabsorption of calcium and hypercalciuria resulting from protein consumption are associated with serum insulin levels. Arginine stimulation of insulin secretion also results in hypercalciuria. The present study was designed to test whether the calciuria associated with arginine-stimulated insulin secretion is mediated by insulin inhibition of parathyroid hormone (PTH) activity. Parathyroidectomized (PTX) and sham-operated rats were infused with physiological saline, or with 12 mmol X kg-1 X hour-1 arginine in saline at 1.2 ml/hour. Analysis of data from clearance periods 90-150 minutes after infusions commenced show that arginine infusion increased urine volume, and calcium excretion (nanograms/minute and nanograms/milliliter glomerular filtration rate), to the same extent in PTX and sham-operated animals. PTH does not, therefore, appear to be involved in the calciuretic response to amino acid infusion.