Subnormal concentrations of urinary epidermal growth factor in patients with kidney disease

Increased Salivary Concentration of Human Epidermal Growth Factor in Patients Undergoing CAPD

Epidermal growth factor (EGF) was measurea In the saliva of 36 patients with chronic renal failure (CRF) and 29 matched control subjects. Salivary EGF in controls was 0.65±0.009 nmol/L compared with 0.99±0.24 nmol/L in nondialyzed CRF patients, 1.15±0.23 in hemodialyzed patients and 1.96±0.25 (p < 0.01, Wilcoxon Rank Sum Test) in CAPO-treated patients. On Sephadex chromatography, the major peak of immunoreactive EGF from patient and control saliva samples coeluted with purified human EGF. We conclude that salivary concentrations of human EGF are significantly elevated in end-stage renal failure, particularly in patients treated by CAPO.

Renal content and output of epidermal growth factor in long-term adrenergic agonist-treated rats

This study investigates the renal and urinary levels of epidermal growth factor (EGF) in rats under long-term treatment with alpha- or beta-adrenergic agonists. Urine samples were obtained on days 7, 14 and 21, and renal tissue samples on day 21. EGF was quantified by ELISA and tissue sections were used for immunohistochemistry and in situ hybridization. Fractional kidney weight was increased in the alpha-adrenergic agonist-treated group by 35% when compared with controls. Histological examination of the kidney revealed well-defined wedge-shaped areas of tubular dilatations and luminal amorphous material in the distal tubules. Concomitantly, reduced levels of EGF and EGF mRNA were observed, and also the urinary levels of EGF were reduced. Together, these observations indicate alpha-adrenergic treatment to affect the distal tubules. Treatment with the beta-adrenergic agonist did not change fractional kidney weight, but initially the urinary excretion of EGF was reduced. The data add further evidence to the suggestion that activity of the sympathetic nervous system influences renal homeostasis of EGF, either directly or indirectly through renal histopathological changes.

Decreased urinary epidermal growth factor in children with acute renal failure: epidermal growth factor/creatinine ratio not a reliable parameter for urinary epidermal growth factor excretion

To verify some animal experimental results in humans, we have studied urinary epidermal growth factor (EGF) excretion in normal children as well as children with acute renal failure (ARF). Urinary EGF excretion was expressed as a ratio of urinary EGF to urinary creatinine concentration (EGF/Cr) for random and 24-h urine, and a daily total urinary EGF for 24-h urine. The highest urinary EGF/Cr in children was found at 1 mo to 3 y of age. There was a highly significant correlation between random urine EGF/Cr and 24-h urine EGF/Cr (r = 0.92, p < 0.001), whereas no correlation of urinary EGF/Cr with daily total urine EGF was found. During the course of ARF, a decline in urinary EGF/Cr from the period before peak serum creatinine to the period after the declination of serum creatinine was noted (p = 0.013, n = 13, by repeated measure analysis), with a constant low daily total urine EGF (p value not significant). However, a rise in both urinary EGF/Cr and daily total urine EGF was found between the period of serum creatinine decline and the period of completely normal serum creatinine (p < 0.001). Serum EGF remained unchanged throughout the course of ARF. These results suggest 1) the possible role of EGF in renal growth or maturation during the first 2 or 3 y of life, 2) the possible renal origin of human urinary EGF, and 3) decreased urinary EGF excretion in children with ARF. In particular, EGF/Cr is not a reliable indicator for the expression of actual urinary EGF excretion in ARF. Instead of urinary EGF/Cr, urinary EGF concentration may be used to predict the daily total urinary EGF excretion during ARF. These results provide the pattern of urinary EGF excretion during ARF in children and may be of help for further clinical studies.

Urinary excretion of epidermal growth factor in living human kidney donors and their recipients

Epidermal growth factor (EGF) is a growth-promoting peptide that is synthesized in the distal tubules of the kidney and excreted in urine. EGF has been suggested to play a role in the repair after renal tissue damage, as well as in compensatory growth of the remaining kidney after uninephrectomy. The present study examined the urinary EGF excretion after uninephrectomy and transplantation among relatives. The urinary EGF excretion rate and the glomerular filtration rate (GFR) were followed for 26-54 days in 16 healthy kidney donors and nine recipients. After uninephrectomy the median urinary EGF excretion rate in the donors was not 50% of the pre-operative value, but around 65% (95% confidence limits of the median on the fifth post-operative day: 59-72%). This suggests that there is a compensatory increase in the EGF excretion rate from the remaining kidney of around 30% after uninephrectomy. A similar compensatory increase was demonstrated for GFR, indicating that the compensatory changes in EGF excretion rate and GFR might be correlated. In the transplanted kidneys, GFR was consistently around 15% lower and EGF excretion rate around 40% lower than in the corresponding kidneys remaining in the donors. This might reflect ischaemic and drug-induced damage of the transplanted kidneys. The present study demonstrated a compensatory increase of around 30% in urinary EGF excretion from the remaining kidney after uninephrectomy in healthy humans. Whether EGF plays a role in the adaptive processes in the remaining kidney or whether changes in EGF excretion are merely of a secondary nature is still uncertain.

Recovery of epidermal growth factor in voided urine of patients with bladder cancer

Epidermal growth factor (EGF), a potent mitogen and tumor promoter, is excreted in urine permitting it to incubate with urothelial cells. We have previously shown that the distribution of receptors for EGF (EGF-Rs) on malignant urothelium changes to favor contact between EGF-Rs and intraluminal EGF. OBJECTIVES. To determine if concentrations of EGF in voided urine are different in patients with transitional cell carcinoma (TCC) of the bladder than in those without this condition. METHODS. EGF was measured by radioimmunoassay in the urine of 54 patients with newly diagnosed TCC (16 with grade 1, Stage Ta lesions, and 38 with grade 3, Stage T > or = 2 lesions) and 66 pathologic and normal controls without TCC. Subjects were matched for age and good renal function. RESULTS. EGF concentrations were significantly reduced in patients with TCC compared with controls either when uncorrected (p < 0.0001) or corrected (p < 0.000000002) for urinary creatinine excretion. CONCLUSIONS. The reduced concentration of EGF in voided urine supports previous evidence that the urinary EGF/urothelial EGF-R interaction is important for TCC development and growth, and has the potential to serve as a marker of tumor persistence, recurrence, and therapeutic response.

Influence of kidney or heart transplantation on the urinary excretion of epidermal growth factor

We studied urinary epidermal growth factor (uEGF) in kidney transplant patients with normal and elevated serum creatinine, in cardiac transplant patients with normal serum creatinine, and in patients with chronic renal failure. Patients with chronic renal failure had the lowest uEGF levels. uEGF was reduced in normally functioning kidney transplant patients. If the kidney graft was failing, this reduction was more marked. Cardiac transplant patients had normal uEGF. The type of immunosuppressive therapy did not influence the uEGF excretion. Kidney function and kidney tissue mass appeared to be the most important factors in uEGF excretion.

An assessment of immunoreactive epidermal growth factor in urine of patients with urological diseases

To examine the excretion of urinary epidermal growth factor (EGF) in urological diseases and the relationship of EGF urine levels with transitional cell carcinoma (TCC), we measured the concentration of EGF by radioimmunoassay. The series comprised patients with active TCC (n = 52), others in tumor-free status (n = 29) and with non-neoplastic inflammatory diseases (n = 43), and normal controls (n = 50). Urinary EGF values were lower in patients with urological diseases of different etiologies than in normal controls (P < 0.005). Mean EGF levels of patients who had previous bladder tumor resection (n = 21) were not statistically different from normal controls (P = 0.2). For patients with active TCC, EGF urine levels showed a significant inverse relationship to increasing tumor grade (P = 0.02). In addition, subjects who had received nephrectomy for pelvic carcinoma (n = 8) showed significantly lower mean EGF values than those with intact kidneys (n = 21), irrespective of sex (P < 0.05). Immunostaining of EGF on non-neoplastic kidney (n = 9) revealed reactivity in the distal convoluted tubules and thick ascending limbs of Henle. Our results suggest that the kidney is the major source of urinary EGF. Its excretion in urine is decreased in both inflammatory and neoplastic diseases of the urinary tract. EGF may play an important part in the biological activity of TCC. Further study is indicated to investigate the monitoring of EGF urine levels as a marker of recurrence for EGF receptor-positive TCC.

Epidermal growth factor in acute renal failure

Epidermal growth factor (EGF) is produced in large amounts in the kidney in the form of a membrane-bound high molecular weight precursor. This precursor is inserted in the apical plasma membrane of the EGF-producing cells, which are localized in the thick ascending limb and distal convoluted tubule in mouse and rat kidney, and probably also in human kidney. High levels of EGF are excreted in urine, although renal tissue contains little mature EGF. It modulates renal cell proliferation and differentiation in vitro, but the role of the distal tubular EGF and/or its precursor in vivo is unknown. The expression of EGF in the kidney and its liberation into the urine are quickly abolished during several types of drug- or ischemia-induced acute renal failure and also in ureteral obstruction. Moreover, its expression is restored only after morphological and functional recovery of the kidney. This absence of EGF in conditions in which its mitogenic properties would be most appropriate suggests that the EGF of renal origin is not acting as a mitogen during kidney regeneration. Nevertheless, since the number of EGF receptors, which are localized at the basolateral cell surface in most nephron segments, is increased in regenerating renal epithelia, EGF of systemic origin or other members of the EGF family of growth factors, released from infiltrated inflammatory cells at the sites of injury, could enhance cellular proliferation by interacting with the EGF receptor. Administration of EGF indeed has a mildly beneficial effect on recovery from acute renal injury.

Urinary epidermal growth factor levels in patients with acute renal failure

To investigate the importance of epidermal growth factor (EGF) in patients with renal dysfunction, urinary human EGF (hEGF) levels were determined by radioimmunoassay in 16 patients with acute renal failure (ARF) and in 12 healthy controls. Seven patients with chronic renal failure also were studied. Urinary hEGF levels, corrected for urine creatinine concentrations, were significantly decreased in patients with ARF in the acute phase compared with normal control subjects (0.98 +/- 0.20 v 13.74 +/- 1.18 ng/mg creatinine, P < 0.001), and subsequently increased during the recovery phase (6.10 +/- 0.73 ng/mg creatinine, P < 0.001 v acute phase). A significant positive correlation existed between urinary hEGF levels and creatinine clearance in patients with ARF (r = 0.66, P < 0.001). Serum hEGF levels also were significantly lower in patients with ARF compared with normal control subjects (0.10 +/- 0.01 v 0.30 +/- 0.03 ng/mL, P < 0.001). No significant correlation was found between hEGF concentrations in serum and urine. In conclusion, measurement of urinary hEGF may be useful in the diagnosis of ARF and for following the recovery of the kidney after severe tubular injury.

Effect of water deprivation, desmopressin (DDAVP) infusion, and oral loads of water, Na+ and NH4+ on urinary excretion of epidermal growth factor in the rat

Epidermal growth factor (EGF) is synthesized in the kidneys and excreted in urine. Administration of exogenous EGF modulates the reabsorption of Na+ and the vasopressin stimulated reabsorption of water in the collecting tubules. In order to clarify whether this reflects a physiological role for urinary EGF we examined the effects of changes in the oral loads of water, Na+ and NH4+ as well as the effect of infusion of the vasopressin analogue, desmopressin (DDAVP) on the endogenous urinary EGF excretion in the rat. Water deprivation for 48 h reduced the urinary excretion of EGF by 25% and the urinary EGF/creatinine ratio by 8%. Also, urinary volume, Na+ excretion, and urinary pH were reduced by water deprivation. Infusion of DDAVP, low plasma vasopressin induced by polydipsia, and changes in the renal excretion of Na+ and H+ did not affect the urinary excretion of EGF.

IN CONCLUSION

it seems unlikely that nephrogenous EGF excreted in the urine plays a physiological role in the regulation of the renal excretion of Na+ and H+ and in the vasopressin stimulated reabsorption of water in the rat. However, since water deprivation reduced the urinary excretion of EGF it remains possible that urinary EGF plays a role in the complex physiological response to dehydration.

Excretion of urinary epidermal growth factor in non-insulin dependent diabetes mellitus

Morning urine samples were assayed for human EGF (hEGF) in 137 non-insulin dependent diabetic patients with normal serum creatinine and beta 2-microglobulin levels. Serving as controls, 80 age- and sex-matched healthy subjects were also examined. A significant positive correlation between hEGF excretion and the level of hemoglobin A1C (HbA1c) was present in those patients with a HbA1c value exceeding 8% (r = 0.37; p = 0.003) but not in the overall patients. The urinary hEGF level did not correlate with the concentration of glucose in urine or plasma. The mean urinary hEGF level of diabetic patients was significantly lower than that of healthy subjects. The mean urinary hEGF level was significantly lower in the patients with a diabetic history that exceeded five years as compared with those with a history below five years. The mean urinary hEGF level was significantly lower in the patients with retinopathy vs. those without retinopathy. In the patients with HbA1c value below 8%, the mean urinary hEGF level was lower in the patients whose urinary albumin level exceeded 1.7 mg/mmol.creatinine as compared with those whose urinary albumin excretion was below 1.7 mg/mmol.creatinine. These findings suggest that urinary hEGF excretion may decrease with the progression of diabetic complications in the patients with well-controlled glycemia, and that inadequate glycemic control may lead to an increased excretion of urinary hEGF in the early disease stage.

Origin of urinary epidermal growth factor in humans: excretion of endogenous EGF and infused [131I]-human EGF and kidney histochemistry

1. This study examined (i) whether blood-infused epidermal growth factor (EGF) can pass into urine; (ii) whether infused labelled EGF behaves like endogenous plasma immunoreactive EGF; and (iii) which parts of the human nephron show morphological evidence of EGF synthesis? 2. We infused human [131I]-EGF into a volunteer. After 6 min, only 66% of the plasma counts represented intact EGF. At the end of infusion, the T1/2 of EGF was calculated to be 1.6 min. The tail of the curve lasted for at least another 2 h. The total excretion of the labelled EGF was 2.45% of the infused dose and was proportional to the urine volume. 3. After a water load, the excretion of endogenous EGF was, on the contrary, inversely related to urine volume. 4. Immunohistochemically, human kidneys were not stained by monoclonal anti-EGF antibodies but showed positive in situ hybridization for EGF mRNA in the nuclei of glomerular mesangial cells, distal convoluted tubules and collecting tubules. 5. We conclude that human kidneys synthesize EGF and release it into urine. Plasma-derived EGF constitutes under normal conditions only a small part of the urinary EGF. Contrasting volume-dependency of the excretion of endogenous and [131I]-EGF requires further study and cautions against extrapolating results obtained with labelled EGF to physiological conditions.

Immunoreactive low-molecular-weight epidermal growth factor in urine of patients with renal cell carcinoma

A specific heterogeneous enzyme-linked immunosorbent assay (ELISA) has been established in order to determine levels of low-molecular-weight epidermal growth factor (EGF) in the urine of patients with renal cell carcinoma who had undergone unilateral radical nephrectomy. Urine specimens, i.e., 20 pre- and postsurgical specimens from a group of patients and 22 from a control group, were assayed after the urine had been freed from high-molecular-weight proteins (greater than 30 kDa) and salts. EGF levels were expressed as urinary EGF/creatinine ratios, and a highly significant decrease (alpha = 0.0005 by Student's t-test) of urinary EGF was found in the patient group prior to surgery. The cancer patients also showed an additional loss of urinary EGF after unilateral nephrectomy (alpha = 0.0005 by Student's t-test). These data correlate with our previous findings that pro-EGF gene expression is decreased in human renal carcinoma and support the concept that low-molecular-weight urinary EGF is derived from high-molecular-weight kidney pro-EGF.

Decreased urinary epidermal growth factor levels in diabetic patients

Urinary human epidermal growth factor levels were assayed in diabetic patients and controls before and after surgery. The preoperative levels in the diabetic patients were decreased and postoperatively, did not show the trough and peak pattern which was seen in the controls.

Excretion of epidermal growth factor (EGF) in diabetes

Excretion of epidermal growth factor (EGF) is decreased in renal failure. We assayed it in diabetes mellitus in an attempt to relate it to clinical parameters, esp. those of diabetic nephropathy. EGF excretion declined with age but in all age groups of diabetic patients was below the first percentile for controls. In 26 control and 34 prepubertal diabetic children excretion was correspondingly 1126 +/- 442 and 932 +/- 489 pmol/mmol creatinine (P = 0.087); in 26 control and 42 diabetic adolescents below age 18, 778 +/- 222 and 676 +/- 335 (P = 0.023) and in 81 control and 83 diabetic adults, 371 +/- 153 and 235 +/- 140 (P less than 0.0001). Decreased excretion of EGF was seen in some patients without any diabetic complications. Excretion of EGF was independently and inversely correlated with age and duration of diabetes but not with type of diabetes, treatment, body built, C-peptide, plasma glucose, glycohemoglobin or retinopathy. A positive correlation was seen with creatinine clearance and a negative correlation, with albuminuria, but the strongest and the only independent correlation found by stepwise multiple variable selection was with serum creatinine (r -0.711, P less than 0.0001). EGF excretion was not elevated in patients with hyperfiltration. We conclude that EGF excretion is abnormal in many patients with diabetes and that this abnormality reflects a kidney function different from glomerular filtration or glomerular permeability.

Relationship of thyroid disease to renal cell carcinoma. An epidemiologic study

Thyroid hormone participates in numerous cellular functions besides thermogenesis and metabolism. Several studies, including the recent identification of the product of an oncogene, c-erb-A, as a thyroid-hormone receptor, have shown possible involvement of thyroid hormone in the process of carcinogenesis. A recent anecdotal observation of an unusually high incidence of thyroid dysfunction in women with renal cell carcinoma led to a retrospective review of the incidence and distribution of thyroid disorders in women with renal cell carcinoma compared with a control group of women with transitional cell carcinoma of the renal pelvis, ureter, bladder, or urethra. Women with renal cell carcinoma had a statistically significantly higher percentage of hypothyroidism, thyroid disease in general, and the use of thyroid-hormone supplements as compared with the control group (P = 0.033, P = 0.005, P = 0.041, respectively). The nature of the relationship, however, could not be determined. These findings add a new dimension to renal cell carcinoma, and prospective studies are encouraged to define the contribution of thyroid hormone to renal cell carcinogenesis.

Excretion of epidermal growth factor-like material in acute Henoch-Schönlein purpura nephritis

In Henoch-Schönlein purpura nephritis (HSPN), glomeruli may develop cellular "crescents" composed of infiltrating monocytes and proliferating renal epithelia. In this study, we demonstrate that peripheral human monocytes can release an epidermal growth factor (EGF)-like substance detectable by a radioreceptor assay, which recognizes both EGF and transforming growth factor-alpha (TGF-alpha), but not with a radioimmunoassay, which recognizes only EGF. Furthermore, we report that urine from pediatric patients during the acute phase of HSPN contains a similar EGF-like species in addition to the endogenous EGF which is normally present. The EGF-like material was not present in urine from nine healthy children or from six children with acute post-streptococcal glomerulonephritis. The extent of crescent formation in our patients is uncertain, since renal biopsy was performed in only one case. However, we speculate that the urinary material resembling TGF-alpha which appears during the acute phase of HSPN may derive from monocytes infiltrating the kidney.

Urinary excretion of human epidermal growth factor in the various stages of diabetic nephropathy

Epidermal growth factor (EGF) is a polypeptide mitogen first isolated from mouse submaxillary glands and later from human urine. We have examined the pattern of urinary excretion of human EGF (hEGF) in normal subjects and in diabetic patients with varying degrees of nephropathy. hEGF was measured by homologous radioimmunoassay and expressed in terms of urinary creatinine excretion. On the basis of their albumin excretion rate, the diabetic patients were divided into those with normoalbuminuria (albumin excretion rate 3.5 (1.4-9.8) micrograms/min; mean (range)), microalbuminuria (albumin excretion rate 75 (30-128) micrograms/min) and macroalbuminuria (289 (169-879) micrograms/min). The albumin excretion rate for the normal subjects was 3.7 (1.6-9.7) micrograms/min. The mean (range) hEGF excretion (nmol hEGF/mmol creatinine) was 0.69 (0.47-1.29) for 19 healthy subjects, 0.60 (0.16-1.36) for the normoalbuminuric group (n = 18; NS), 0.47 (0.10-0.83) for the microalbuminuric patients (n = 19; P less than 0.001 vs controls and normoalbuminuric diabetics) and 0.38 (0.10-0.63) for the macroalbuminuric group (n = 18; P less than 0.001 vs controls and normoalbuminuric diabetics). There was an inverse correlation between albumin excretion rate and hEGF: creatinine ratio (r = -0.49; P = 0.02). These results show a progressive decline in hEGF excretion in diabetic patients with varying degrees of nephropathy and do not support the hypothesis that increased kidney size seen in early nephropathy is due to excessive amounts of EGF in the urine.

Reduced urinary excretion of epidermal growth factor in incipient and overt diabetic nephropathy

To study the relationship between glomerular and tubular function we investigated glomerular filtration rate (GFR), urinary albumin excretion, and urinary excretion of epidermal growth factor (EGF, a mitogenic peptide synthesized in the renal tubular cells) in normal subjects (group I, n = 7) and in Type 1 (insulin-dependent) diabetic patients with normoalbuminuria (group II, n = 11); with incipient nephropathy (microalbuminuria) (group III, n = 9); with nephropathy and normal GFR (group IV, n = 12); and with reduced GFR (group V, n = 8). EGF (nmol 24 h-1) decreased with progressive glomerular involvement, from 7.9 (4.1-10.5) (median and range) in group I, to 6.7 (1.3-9.2) in group II, 5.0 (3.6-7.4) in group III, 4.1 (2.5-9.5) in group IV, and 1.1 (0.1-2.5) in group V. The urinary excretion of EGF was significantly reduced in patients with elevated UAE (group III, IV, and V) compared with normal control subjects (p less than 0.05). A significant correlation between urinary excretion of EGF and GFR (r = 0.71, p less than 0.001) and an inverse correlation between the urinary excretion of EGF and albumin (r = -0.35, p less than 0.05) was demonstrated in the Type 1 diabetic patients with GFR greater than 90 ml min-1. Our study demonstrates that urinary excretion of epidermal growth factor diminishes with increasing nephron impairment, and that renal tubular function as judged by the excretion of EGF is reduced early in the development of diabetic kidney disease.

Epidermal growth factor excretion and receptor binding in diabetic rats

Urinary epidermal growth factor (EGF) excretion was calculated as ng EGF per mg creatinine and ng EGF per 24 hr. It was increased 4-9 fold in rats with genetic (BB) or streptozotocin-induced diabetes. It decreased to 2-3 fold control values in insulin-treated animals. In contrast, EGF concentration in serum was lower in diabetic than in control rats (360 +/- 72 vs 524 +/- 150 pg/ml, P .086); EGF level in plasma was unchanged (319 +/- 67 vs 313 +/- 96 pg/ml). In diabetic rats EGF content was increased in submaxillary glands (1018 +/- 259 vs 738 +/- 122 pg/mg protein, P .060) but unchanged in the kidneys (70 +/- 18 vs 65 +/- 6 pg/mg protein in controls). EGF binding to the liver microsomes in diabetic rats was decreased by 30-40% and was not restored by insulin therapy. Binding to the kidneys also showed a tendency to decrease in diabetic animals. The EGF excretion and receptor binding were normal in obese normoglycemic Zucker fa/fa rats. We suggest that hyperglycemia and/or glucosuria may affect EGF synthesis and/or excretion in the kidneys and EGF synthesis or accumulation in the megakaryocytes. The mechanism of decreased EGF receptor binding remains to be clarified.

Urine human epidermal growth factor (hEGF) levels following surgery

In order to investigate the contribution of growth factors in conditions of postoperative stress, we measured the blood and urine hEGF levels in patients with various surgical disorders. While the levels of serum and plasma hEGF did not change significantly after surgery, urine hEGF (u-hEGF) stayed at the base-level followed by a single peak within a postoperative period of two weeks. The peak day of u-hEGF in patients with more than 1000 ml of intraoperative bleeding was later than that in patients with bleeding of less than 1000 ml. In patients with postoperative renal failure or dysfunction, u-hEGF levels dropped and did not rise until the recovery of renal function. The changing pattern of u-hEGF levels was an indicator of operative bleeding volume and renal function.

Human epidermal growth factor: renal production and absence from plasma

Among the unsettled questions in the physiology of human epidermal growth factor (EGF) are (1) does EGF circulate in the blood and (2) what is the source of the abundant urinary immunoreactive EGF (irEGF). Therefore, we monitored the concentration of irEGF by an ultrasensitive assay in blood plasma from 5 healthy subjects every 20 min overnight carefully avoiding activation of platelets. Detectable levels (0.8-3.7 pM) were observed in only one of the subjects, in 5 of 29 samples. In random day-time plasma samples from 18 healthy adults, EGF was undetectable (less than 0.8 pM) in 13 subjects, and in 5 subjects EGF levels ranged from 2.2 to 4.9 pM. Furthermore, in 5 patients with a tumor in a functioning kidney we measured urinary relative irEGF concentration (nmol/mmol creatinine) before and after unilateral nephrectomy. The concentration fell by approximately 50%. Our findings are consistent with (1) blood irEGF residing exclusively in platelets, and (2) urinary irEGF originating from the kidneys.

Urinary epidermal growth factor excretion and breast cancer risk

The amount of urinary epidermal growth factor (EGF) excreted was determined in 350 normal women of whom 37 subsequently developed breast cancer. These were a group of women selected on a case-control basis from 5000 volunteers who had participated in a prospective epidemiological study. Urinary EGF excretion was not correlated with known risk factors such as age at menarche or menopause, age at first or last full-term child or parity. Neither was it associated with day or length of menstrual cycle, breast mammographic parenchymal pattern or the blood concentration of prolactin, dehydroepiandrosterone or its sulphate ester. Univariate analysis indicated that the amount of urinary EGF was significantly correlated with urinary creatinine (P less than 0.001), age (P less than 0.001), urinary androsterone (P less than 0.02) or aetiocholanolone (P less than 0.02), height (P less than 0.05) and weight (P less than 0.05). However, multivariate analysis showed that the amount of urinary EGF was correlated only with creatinine excretion (P less than 0.001) and age (P less than 0.001) and that the significance of the other correlations were probably due to the confounding influence of creatinine.

Urinary epidermal growth factor concentrations in various human malignancies

We determined the concentrations of immunoreactive epidermal growth factor in the urine (U-irEGF) of 97 adult patients with various malignancies, including carcinomas of the urinary bladder, kidney, stomach, colon, rectum, breast, endometrium, uterine cervix, ovary, vagina, prostate, pancreas and thyroid, liposarcoma and skin melanoma. The relative U-irEGF concentrations (ng m-1 creatinine) were higher (P = 0.002) for the whole series of female patients than for healthy controls matched for sex and age. Such difference did not appear for male patients. The only specific group with a statistically supranormal U-irEGF concentration (P = 0.0005) comprised women with endometrial carcinoma of the uterus.

The source of urinary epidermal growth factor in humans

To clarify the source of human urine EGF, we studied EGF renal clearance in 20 healthy, young adult subjects. Immunoreactive EGF was measured hourly in EDTA plasma, heparin plasma, serum and urine of 12 males and 8 females during a 3 h study period. Plasma and urine creatinine and creatinine clearance were measured and calculated hourly. Mean (and SEM) creatinine clearance was similar in males and females (118 +/- 12 vs 105 +/- 6 ml/min). EGF was not detectable in plasma, whereas relatively high levels were measured in serum (2.5 +/- 0.25 vs 1.5 +/- 0.18 ng/ml in males and females respectively p less than 0.05). Urine EGF excretion averaged 1641 +/- 233 ng/h in males and 1507 +/- 191 ng/h in females (p greater than 0.05). A significant correlation was observed between urine creatinine and urine EGF concentrations in both male (r = 0.98, p less than 0.01) and female (r = 0.94, p less than 0.01) subjects. EGF immunoreactivity in urine and serum eluted from G-75 sephadex columns similarly to recombinant 6000 Mr hEGF. Urine excretion of EGF approximated 1.5 micrograms/h or 25 ng/mg creatine. The high concentrations of EGF found in urine in the face of non-detectable levels of EGF in plasma favor the hypothesis that EGF in urine is derived from kidney synthesis and secretion. The significant positive correlation between urine creatinine and urine EGF suggests a functional correlation between glomerular filtration and the process of tubular EGF excretion.

Human epidermal growth factor concentrations in urine, but not in saliva and serum, depend on thyroid state

To evaluate the effects of thyroid hormones on the concentration of epidermal growth factor (EGF), we determined values for the immunoreactive EGF concentration in the urine (U-irEGF) of newborn infants with congenital hypothyroidism (N = 19), and in urine, saliva and serum of adult patients with hypothyroidism (N = 11) and hyperthyroidism (N = 8). The values were expressed as SD score (SDS), i.e. deviation in SD units from their mean value of healthy subjects of the same age and sex. The SDS of relative U-irEGF (ng/mg creatinine) was lower (P less than 0.01) in newborn infants with congenital hypothyroidism (-0.8 +/- 0.2; mean +/- SEM) than in healthy infants. Their relative U-irEGF correlated with their serum T4 concentrations (r = 0.59, P less than 0.01). The SDS of relative U-irEGF was lower (P less than 0.01) in adult hypothyroid patients (-1.2 +/- 0.5) and higher (P greater than 0.05) in adult hypothyroid patients (0.9 +/- 0.6) than in healthy adult subjects. When subsequently euthyroid, their SDS of relative U-irEGF increased to -0.5 +/- 0.3 (P less than 0.01), and decreased to -0.7 +/- 1.1 (P less than 0.05), respectively. The irEGF concentrations in saliva and serum were not significantly different between the hypothyroid and hyperthyroid patients. Our results indicate that urinary excretion of irEGF in man is dependent on thyroid hormone.

Evaluation of epidermal growth factor receptors in bladder tumours

Epidermal growth factor (EGF) receptor expression in 31 primary human bladder tumours was quantitated using both structural and functional assays and the EGF receptor gene in the same tumours was analyzed by Southern blot analysis. Immunocytochemical studies using the EGFR1 monoclonal antibody (Mab) showed a significant correlation between EGF receptor levels and the stage and grade of the tumours. Autophosphorylation assays employed to evaluate the receptor's tyrosine kinase activity gave results which in general were consistent with the immunocytochemical data. Using internally controlled immunocytochemical studies with two Mabs and Southern blot analysis of DNA isolated from the tumours, no evidence was obtained for the production of truncated receptors similar to those encoded by the v-erb-B oncogene. Gene amplification was not found in any of the superficial tumours, but one invasive tumour with high EGF receptor expression had an 8-10 fold amplification of the EGF receptor gene. The EGF receptor isolated from this tumour showed a normal pattern of tyrosine phosphorylation at all three major autophosphorylation sites. Our detailed study is consistent with the correlation previously found between EGF receptor expression and stage and grade of bladder tumours, and suggests that at this level of analysis EGF receptors in bladder tumours are not abnormal in structure or size, autophosphorylation activity, or gene structure.

Human urinary epidermal growth factor: effects of age, sex and female endocrine status

Urinary concentrations of immunoreactive epidermal growth factor (irEGF) were determined by specific homologous radioimmunoassay in 300 healthy women and 163 healthy men between 16 and 93 years of age. Both absolute (ng/ml) and relative (ng/mg creatinine) concentrations decreased with age in both sexes. The relative concentration was higher in women than in men at ages 20-70 years (P less than 0.001), the respective mean values (ng/mg creatinine) being 49.1 and 40.1 at 16-20 years, 58.9 and 41.8 at 20-30 years, 47.6 and 36.9 at 30-45 years, 42.8 and 29.0 at 45-55 years, 44.9 and 30.1 at 55-70 years, and 16.0 and 18.5 in those over 70 years. The values were unaffected by the menstrual cycle, pregnancy, oral contraceptives, or postmenopausal estrogen and/or progestin therapy.