Summary
Effects of insulin on plasma concentration and renal excretion of sodium and potassium
were compared in conscious dogs 1) maintained in water and electrolytes balance (Series
1,10 dogs), 2) depleted of electrolytes by repeated i.v. loading with 20% mannitol
(Series 2, 10 dogs), and 3) aldosterone treated (0.8 μg·kg-1 ·h-1 i.v., Series 3, 10 ogs). In each Series intravenous infusion of insulin at a rate
of 0.05 U·g-1 ·h-1 elicited transient increase in plasma sodium concentration and prolonged hypokalemia.
Repeated loading with mannitol in Series 2 elicited significant elevation of plasma
sodium, ADH and aldosterone concentrations, as well as decrease in extracellular fluid
volume. Infusion of insulin in this Series elicited smaller decrease in plasma potassium
concentration and longer lasting hypernatremia than in dogs in water-electrolytes
balance. Aldosterone infusion in Series 3 did not change hypo-kalemic effect of insulin
but attenuated hypernatremia. Infusion of insulin in Series 1 elicited increase of
sodium excretion and decrease in potassium excretion. These effects were absent in
Series 2 and 3. The results indicate that depletion of electrolytes and blood aldosterone
elevation modify the effects of insulin on plasma concentration and renal excretion
of sodium and potassium.
Key-Words
Insulin
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Aldosterone
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Electrolytes Depletion
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Sodium Excretion
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Potassium Excretion
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Plasma Sodium
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Plasma Potassium
