Epidermal growth factor (urogastrone) in human tissues.

Area of Science:

• Biochemistry
• Endocrinology
• Molecular Biology

Background:

• Human epidermal growth factor (hEGF) stimulates tissue growth and is found in high amounts in human urine.
• hEGF is likely identical to human beta-urogastrone (hUG), a gastric acid secretion inhibitor.
• The primary tissue source of hEGF/hUG remains unidentified.

Purpose of the Study:

• To identify the primary tissue source of human epidermal growth factor/human beta-urogastrone (hEGF/hUG).

Main Methods:

• Extraction of hEGF/hUG from human tissue homogenates using cation exchange and immune affinity chromatography.
• Radioimmunoassay (RIA) for homologous hEGF detection.
• Characterization of immunoreactive hEGF using Sephadex G-50 gel filtration.

Main Results:

• Immunoreactive hEGF was detected in adult submandibular gland, thyroid gland, duodenum, jejunum, and kidney.
• Concentrations of immunoreactive hEGF in these tissues were very low (1.3-5.5 ng/g wet tissue).
• No immunoreactive hEGF was found in several fetal tissues examined.

Conclusions:

• The identified adult tissues contain very low levels of hEGF/hUG, making their role as the primary source uncertain.
• Further investigation is needed to pinpoint the source of the large quantities of hEGF/hUG excreted daily.
• The kidney's role in filtering hEGF/hUG suggests potential renal involvement or filtration of a systemically produced factor.