Basal level of epidermal growth factor in gastric juice of 86 healthy Chinese volunteers by radioimmunoassay

Li Zhang, Ming Liang Zhang, Yue Qing Yan,  Da Xing Liang

Subject headings  gastric juice; epidermal; growtu factorl analysis; radioimmunoassayª¤

Zhang L, Zhang ML, Yan YQ, Liang DX. Basal level of epidermal growth factor in gastric juice of 86 healthy Chinese volunteers by radioimmunoassay. China Nati J New Gastroenterol, 1997;3(4):245



INTRODUCTION
Epidermal growth factor (EGF) is a low molecular weight polypeptide consisting of 53 amino acid residues^£Û1£Ý. Its main sources are the submaxillary and Brunner¡äs glands. EGF is distributed all over the gastrointestinal tract. Its concentration is higher in gastric juice. So far, the precise value of EGF in gastric juice in normal subjects has not been reported in China. In this investigation we measured the basal level of EGF by RIA in 86 healthy volunteers from different age groups.

MATERIALS AND METHODS

Subjects
Eighty-six healthy volunteers, included 24 children (male 18, female 6; age 8-9 years) 28 college students (male 16, female 12; aged: 18-20  years) and 34 adults over 40 years of age (male 20, female 14).

Methods
Special capsules for collecting minute quantities of gastric juice were swallowe d by the 86 subjects under basal condition before 8 a.m. in the morning. After staying in the stomach for 20 minutes, the capsules were pulled out, each containing 0.3mL-0.5mL of gastric juice. The specimens were preserved for use at £­40¡æ. Before measurement and analysis, the gastric juice was centrifuged at 2000r for 30 minutes at 4¡æ. 0.1mL supernatant was measured for EGF by RIA according to the method of Lu GJ^£Û2£Ý.

RESULTS
The average concentration of EGF in the gastric juice among the 86 healthy volun teers under basal condition was 0.62¦Ìg/L¡À0.15¦Ìg/L. While the values of EGF in children (n=24), young adults (n=28) and middle aged groups (n=34 were 0.61¦Ìg/L¡À0.14¦Ìg/L, 0.65¦Ìg/L¡À0.14¦Ìg/L and 0.59¦Ìg/L¡À0.13¦Ìg/L respectively. The EGF level among males (n=52) was 0.61¦Ìg/L¡À0.14¦Ìg/L and among females 0.62¦Ìg/L¡À0.15¦Ìg/L. No stastistically significant differences were noted between different age and sex groups.

DISCUSSION
The major sources of EGF are the submaxillary gland and Brunner¡äs gland of duodenum. It is belived that EGF can inhibit secretion of gastric acid and stimulate DNA synthesis. It also plays a role in protection of gastrointestinal mucosa^£Û3£Ý. It was higher in gastric juice. The exact concentration of EGF in normal gastric juice so far has not been well defined. One of the causes was the inconvenience in collecting specimens of gastric juice. The conventional gastric tubing and gastroscopy would cause discomfort while the swallowed capsule for obtaining minute specimens of gastric juice is easily accepted by both children and adults. Since the EGF level might be an important variable in evaluating health status, more data could be accumulated. This method is useful for further investigation in various benign and malignant diseases of gastrointestinal tract.

REFERENCES
1  Savage RC, Cohen S. Epidermal growth factor and a new derivative: rapid isolation procedures and chemical characterization.
    J Biol Chem, 1972;247(22):7609-7611
2  Lu GJ, Hou X, Cheng YF, Huan BR, Chai LW. Radioimmunoassay of human epidermal growth factor (h-EGF) and characterization
    of domestically produced antiserum against h-EGF by genetic engineering. Chin J Nucl Med, 1993;13(1):22-24
3  Konturek SJ, Brzozowski T, Jaworek J. Role of growth factor in gastroduodenal protection and healing of peptic ulcer.
    Gastroenterol Clin North Am, 1990;19(1):41-43

Department of Digestive Research, the Second Affiliated Hospital of Hengyang Medical College, Hengyang 421001, China
*Supported by the Health and Scientific Foundation of Hunan Province (No.93015).
Correspondence to Dr. Li Zhang, female, was born on July 12, 1964, Yongxing County, Hunan Province, graduated from Department of Medicine, Hengyang Medical College, Physician in Charge, engaged in the diagnostic and therapeutic study on Helicobactor pylori infection, having 7 papers published.
Tel:+86¡¤734¡¤8223251-8405
Received  1996-10-10    Revised  1996-11-10