Renal uptake and excretion of epidermal growth factor from plasma in the rat.
The rat excretes around 2 nmol epidermal growth factor (EGF) in the urine per 24 h. The urinary EGF might be derived from plasma and/or might be synthesized in the kidneys. We have used the rat to study the renal uptake and excretion of homologous EGF from plasma. I.v. injected 125I-EGF was removed from the circulation within a few minutes. 5 min after the injection, the kidneys contained 12% of the 125I-EGF. The kidneys seemed to degrade most of the 125I-EGF which they accumulated from blood, as only 4% of the injected label was excreted as intact 125I-EGF in the urine. The amount of endogenous EGF in plasma was under the detection limit of our enzyme-linked immunosorbent assay (0.03 nmol/l) and it remained so after bilateral nephrectomy. Even if plasma EGF was 0.03 nmol/l excretion of EGF from plasma could account for less than 5% of the urinary EGF. This study shows that the kidneys are able to accumulate EGF from plasma and excrete a part of it as intact EGF in the urine. However, excretion of immunoreactive EGF from plasma can only account for a minor part of the urinary EGF.
Jørgensen
P E
PE
Department of Urology D, Rigshospitalet, University of Copenhagen, Denmark.
Rasmussen
T N
TN
Skov Olsen
P
P
Raaberg
L
L
Seier Poulsen
S
S
Nexø
E
E
D000818:Animals; D001345:Autoradiography; D004815:Epidermal Growth Factor / Q000097:blood / Q000378:metabolism* / Q000652:urine; D007668:Kidney / Q000502:physiology*; D008297:Male; D008657:Metabolic Clearance Rate; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains
D004815:Epidermal Growth Factor