A Rat Model for Hormone and Mineral Changes in Chronic Renal Failure

Plasma parathyroid hormone (PTH) and calcitonin (CT) in rats with surgically induced chronic renal failure were measured by radioimmunoassay. Plasma PTH levels in uremic rats (2897 +/- 693 pg/ml) were significantly (P less than 0.001) higher than those in nonuremic rats (286 +/- 18 pg/ml). A low-phosphorus diet for 4 and 8 days increased serum calcium and decreased the elevated PTH level to the level of sham-operated rats. Plasma CT levels in uremic rats (60.1 +/- 7.8 pg/ml) were significantly (P less than 0.05) higher than those in nonuremic rats (37.6 +/- 2.4 pg/ml). The low-phosphorus diet for 4 days, but not 8 days, increased the CT levels in uremic rats. Our results demonstrate the importance of phosphate and calcium in influencing the secretion of PTH and CT in uremia. The rat, along with appropriate radioimmunoassays, appears to be a useful model for studying bone mineral metabolism in chronic renal failure.