Prolactin-like immunoreactivity in human small-intestinal mucosa

Several peptide hormones are present in both the brain and the gastroenteropancreatic endocrine system. The possibility that prolactin is another 'brain gut' peptide was suggested by the persistently raised serum concentrations of prolactin (>1000 mU/l) found in some patients with coeliac disease with no other obvious cause for the hyperprolactinaemia. We sought prolactin-like immunoreactivity in small-intestinal biopsy specimens using a simple technique for showing gastroenteropancreatic endocrine cells.