Human Beta-microseminoprotein expression, with special reference to gastric mucosa, atrophic corpus gastritis and gastric carcinoids

Abstract: Human Beta-microseminoprotein is a 94 amino acid protein with 10 cysteins present in seminal plasma and on many mucosal surfaces in the body. The function of the protein is unknown. The purpose of this investigation was to study the distribution of Beta-microseminoprotein in the human body, especially in the stomach. The latter was studied under both normal and pathological conditions. A radioimmunoassay for measuring of Beta-microseminoprotein was developed. Tracheobronchial secretion and seminal plasma contain about 1 g/L, gastric juice about 1 mg/L and serum from men and women contain about 1-10 mg/L Beta-microseminoprotein. The synthesis and secretion of Beta-microseminoprotein in gastric mucosa was proved by demonstration of Beta-microseminoprotein mRNA in the mucosa and presence of higher values of Beta-microseminoprotein in gastric juice devoid of tracheobronchial contribution, than in serum. Immunohistochemical staining of the stomach mucosa revealed mucin producing cells (M cells) and cells with endocrine characteristics (E cells) to contain Beta-microseminoprotein. Investigations showed that the majority of E cells also contain chromogranin A and gastrin. Atrophic corpus gastritis entails hyperplasia and hypertrohpy of the E cells and raises serum concentrations of Beta-microseminoprotein. Immunohistochemical presence of Beta-microseminoprotein in gastric carcinoid tumours correlate with tumour progression, which could be of value in the follow up of patients with gastric carcinoid disease.