Plasma calcitonin in rats with renal failure.

To study the effect of the kidney on blood calcitonin (CT), rats were made uremic by either total or partial nephrectomy or bilateral ligation of the ureters. Plasma CT concentrations were measured by radioimmunoassay before and after calcium infusion. Uremia induced by total or partial nephrectomy produced an increase in plasma CT. Rats had higher plasma CT levels (49.3 +/- 1.7 pg/ml, mean +/- SE) after total nephrectomy than after ureteral ligation (30.9 +/- 1.5 pg/ml) even though no significant difference was observed between the blood urea nitrogen (BUN) levels of these two groups. These results indicate that the kidney contributes to the degradation of CT.