EFFECT OF 2-INHIBITORS OF OXIDATIVE-PHOSPHORYLATION ON UREA EXCRETIONIN RATS

The effects of phloretin and carbonyl-cyanide-m-chlorophenylhydrazone (CCCP), both inhibitors of oxidative phosphorylation, on renal urea ex cretion in Wistar rats were investigated. Phloretin and CCCP infusions did not influence plasma urea concentration (P(urea)), compared with controls (0.15 M NaCl and Tris solution in 0.15 M NaCl - a solvent for phloretin and CCCP). The fractional urea excretion (FE(urea)) was not altered by phloretin infusion. It decreased significantly only when c ompared with 0.15 M NaCl infusion (P<0.05). CCCP infusion had no effec t on FE(urea). The total amount of urea excreted by urine (U(urea)V) w as not altered by phloretin compared with controls. CCCP significantly enhanced U(urea) V only when compared with 0.15 M NaCl (P<0.001), not when compared with Tris. Glomerular Filtration rate (GFR) increased s ignificantly during phloretin infusion (P<0.001), CCCP (P<0.001) and a lso after Tris in 0.15 M NaCl (P<0.001), in comparison with 0.15 M NaC l alone. Our results showed that phloretin and CCCP had no effect on u rea excretion in rats. The increase in GFR is attributed to Tris, not to phloretin or CCCP. It is concluded that inhibition of oxidative pho sphorylation in kidney has no effect on urea excretion.