Augmented aldosterone and insulin responses to potassium infusion in dogs with renal failure

The present study examines acute potassium-induced insulin and aldosterone responses in renal failure, and the role of chronic dietary potassium intake in modifying these acute responses. Plasma aldosterone (PA) and insulin (IRI) responses to acute KCl infusion were examined in control and remnant kidney dogs on two potassium intakes. Dogs (N = 8) received the KCl infusions after 10 days of a 60, and then 10 days of a 200, mEq daily potassium intake during control and after surgical-induced renal failure (CRF). A one hour intravenous infusion of KCl (2 mEq KCl/kg/hr) in dextrose and water was performed with blood samples for PA, IRI, creatinine and electrolytes, and urine for electrolytes and creatinine at 20 minute intervals one hour preceding, during, and after the infusion. Preinfusion PA was higher (P less than 0.05) in controls and CRF dogs on 200 mEq potassium intake compared to 60 mEq potassium intake. The peak incremental responses of PA to KCl infusion were increased (P less than 0.01) in CRF compared to controls on 60 mEq (PA 36 +/- 4.2 vs. 26 +/- 3.0 ng/dl) and 200 mEq (delta PA 49 +/- 5.6 vs. 37 +/- 2.8 ng/dl) potassium intakes. Differences in incremental PA responses in CRF were not due to altered aldosterone metabolic clearance rates, changes in renin, or ACTH activity. Pre-infusion IRI was higher (P less than 0.05) in CRF than control dogs on both potassium diets.(ABSTRACT TRUNCATED AT 250 WORDS)