Specificity of the Inhibitory Effect of “Uremic” Serum on p-Aminohippurate Transport ∗

Summary

Addition of serum from bilaterally nephrectomized rats 48 hours after nephrectomy produced a concentration-related inhibition of in vitro PAH uptake by rat renal cortical slices. Simultaneously measured NMN-¹⁴C uptake was not significantly affected. Serum from sham-nephrectomized rats significantly enhanced PAH uptake without altering NMN-¹⁴C transport. Thus, both inhibition of PAH transport produced by serum from nephrectomized rats and stimulation produced by control serum appear to be specific for the organic anion transport system. It is also concluded that the ability of rat renal cortical slices to accumulate PAH is impaired if the animals have been subjected to a 24-hour fast before the time of experimentation. Fasting produced no significant alteration in the transport of NMN-¹⁴C.