The effect of parathyroid hormone on the renal accumulation of lead

Abstract

The effect of parathyroid hormone (PTH) on renal accumulation of lead has been assessed in two experiments on mature rats. In the first experiment, lead was given per os, followed by subcutaneous injections of PTH (100 units of parathyroid extract, Lilly) or vehicle alone over the next 2 days. In the second experiment, anesthetized rats were given lead +/- PTH (bovine 1-34, Beckman; primed with 1.33 [mu]g and a constant infusion of 4.2 ng/minute) intravenously over a 2-hour period. In both experiments, PTH caused significant increments in renal lead concentration (52 and 29%, respectively) compared to groups treated with lead but not PTH. Since total body lead is also increased with PTH treatment in the first experiment, a gastrointestinal (GI) mechanism is suggested; however, stimulation of GI absorption cannot account for the effect in the second experiment in which lead was administered iv. In both experiments, the increment in renal lead in the absence of changes in lead in other soft tissues (liver, red cell, or plasma) suggests a selective effect of PTH on renal lead. The possible mechanisms for this effect are discussed.