Urinary excretion of epidermal growth factor and Tamm-Horsfall protein in three rat models with increased renal excretion of urine

TY - JOUR

T1 - Urinary excretion of epidermal growth factor and Tamm-Horsfall protein in three rat models with increased renal excretion of urine

AU - Thulesen, J

AU - Jørgensen, P E

AU - Torffvit, O

AU - Nexø, Ebba

AU - Poulsen, Steen Seier

PY - 1997/10/31

Y1 - 1997/10/31

N2 - Epidermal growth factor (EGF) and Tamm-Horsfall protein (THP) are synthesized in the kidneys by the distal tubular cells and excreted into urine. The urinary excretion of these peptides has been suggested as a potential index for distal tubular function. The urinary excretion rates of EGF and THP were examined in three groups of rats with increased renal excretion of urine: uninephrectomy, non-osmotic polyuria and diabetic osmotic polyuria. Twenty-four hour urine samples were obtained after 7, 14 and 21 days. The urinary volume per kidney was doubled in uninephrectomy when compared to controls. There was a seven-fold increase in urinary volume in rats with non-osmotic polyuria and diabetic osmotic polyuria, as compared to controls. Uninephrectomy, non-osmotic polyuria and diabetes all affected the urinary excretion of EGF and THP differently. The EGF excretion in uninephrectomized rats was 60-80% of that of the controls, whereas THP excretion was unchanged, indicating that EGF excretion varied with renal tissue mass. Non-osmotic polyuria caused a five-fold increase in THP excretion but no change in EGF excretion. THP excretion in the diabetic rats was increased three-fold after 21 days when compared to controls, whereas EGF excretion was decreased when expressed per kidney weight. Immunohistochemistry demonstrated that EGF and THP were colocalized in the thick ascending limbs of Henle's loops and distal tubules in all five groups of rats. In conclusion, the EGF excretion appears to follow renal tissue mass and seems independent of urinary volume, whereas THP excretion is dependent mainly on urinary volume. This has implications for the use of EGF and/or THP excretion rates as an indicator for distal tubular function.

AB - Epidermal growth factor (EGF) and Tamm-Horsfall protein (THP) are synthesized in the kidneys by the distal tubular cells and excreted into urine. The urinary excretion of these peptides has been suggested as a potential index for distal tubular function. The urinary excretion rates of EGF and THP were examined in three groups of rats with increased renal excretion of urine: uninephrectomy, non-osmotic polyuria and diabetic osmotic polyuria. Twenty-four hour urine samples were obtained after 7, 14 and 21 days. The urinary volume per kidney was doubled in uninephrectomy when compared to controls. There was a seven-fold increase in urinary volume in rats with non-osmotic polyuria and diabetic osmotic polyuria, as compared to controls. Uninephrectomy, non-osmotic polyuria and diabetes all affected the urinary excretion of EGF and THP differently. The EGF excretion in uninephrectomized rats was 60-80% of that of the controls, whereas THP excretion was unchanged, indicating that EGF excretion varied with renal tissue mass. Non-osmotic polyuria caused a five-fold increase in THP excretion but no change in EGF excretion. THP excretion in the diabetic rats was increased three-fold after 21 days when compared to controls, whereas EGF excretion was decreased when expressed per kidney weight. Immunohistochemistry demonstrated that EGF and THP were colocalized in the thick ascending limbs of Henle's loops and distal tubules in all five groups of rats. In conclusion, the EGF excretion appears to follow renal tissue mass and seems independent of urinary volume, whereas THP excretion is dependent mainly on urinary volume. This has implications for the use of EGF and/or THP excretion rates as an indicator for distal tubular function.

KW - Adjuvants, Immunologic

KW - Animals

KW - Diabetes Mellitus, Experimental

KW - Disease Models, Animal

KW - Diuresis

KW - Enzyme-Linked Immunosorbent Assay

KW - Epidermal Growth Factor

KW - Female

KW - Immunohistochemistry

KW - Kidney

KW - Kidney Tubules, Distal

KW - Mucoproteins

KW - Nephrectomy

KW - Organ Size

KW - Osmolar Concentration

KW - Polyuria

KW - Rats

KW - Rats, Wistar

KW - Uromodulin

M3 - Journal article

C2 - 9652978

SN - 0167-0115

VL - 72

SP - 179

EP - 186

JO - Regulatory Peptides

JF - Regulatory Peptides

IS - 2-3

ER -