Renal Excretion of l-Epinephrine in the Dog

¹ From the Department of Physiology, University of Oregon Medical School, Portland, Oregon

The renal excretion of epinephrine was studied in dogs anesthetized with sodium pentobarbital. Epinephrine in plasma and urine was quantitatively estimated by the fluorometric method of Lund. Glomerular filtration rate (creatinine clearance), renal plasma flow (PAH clearance) and PAH transport were employed as parameters of renal function. During periods of intravenous infusion of epinephrine, the percentage of hormone excreted was about 4.6% of that infused. The renal clearance of epinephrine was significantly greater than the glomerular filtration rate though less than renal plasma flow. From this and other information it was concluded that epinephrine is excreted both by tubular transport (tubular secretion) and glomerular filtration. The tubular transport of epinephrine was not inhibited by either 2,4-dinitrophenol or an adrenergic blocking agent.