Acute Effect of Metal Ions on Uptake of Alpha-Aminoisobutyric Acid (AIB) by Rat Parathyroids in vivo.

Summary Acute increases in serum calcium concentration produced by administration of calcium salts, parathyroid extract or high dosages of dihydrotachysterol generally resulted in a decrease in the uptake of AIB by the rat parathyroids in vivo. Acute decreases in serum calcium concentration produced by administration of sodium oxalate, sodium phosphate, or thyrocalcitonin resulted in increases in the uptake of AIB by the parathyroids. Large increases in serum magnesium or strontium concentration also suppressed parathyroid AIB uptake. Administration of EDTA to decrease serum calcium concentration resulted in variable effect on parathyroid AIB uptake. This study provides further direct evidence for a negative feedback control of parathyroid function by serum calcium concentration.