Mechanism of magnesium excretion by the chicken

¹ Medical Service, Veterans Administration Hospital; and Department of Medicine, Duke University Medical Center, Durham, North Carolina

Urinary magnesium excretion was evaluated during the administration of magnesium salts into one leg vein of the chicken by means of the Sperber technique. Changes of magnesium excretion paralleled those of filtered load and sustained unilateral differences of magnesium excretion were not observed. Corrected magnesium-inulin clearance ratios rose to values of approximately 1.0 and remained at that level despite continuing rises of filtered load. The results indicate that magnesium excretion is determined solely by glomerular filtration and tubular reabsorption. Evidence of a tubular secretory system was not obtained.