Interactions of parathyroid hormone and plasma membranes from rat kidney

The initial interaction between parathyroid hormone and isolated purified membrane preparations from rat kidney is probed with the use of a highly tritiated, biologically active derivative of parathyroid hormone, [³H] acetamidino-parathyroid hormone. A method for assaying the binding of the labeled parathyroid hormone to these membranes at nanogram per milliliter concentrations has been demonstrated utilizing this method. The binding described is not reduced by pre-incubations with large excess quantities of other polypeptide hormones, but is qualitatively abolished by pre-incubation with smaller quantities of unlabeled parathyroid hormone. The oxidized, biologically inactive labeled parathyroid hormone does not bind to these membranes.