Protein synthesis by cultured jejunal mucosa from control subjects and patients with coeliac disease.

Jejunal biopsies from patients with coeliac disease and from controls were cultured in vitro for 24 hours with 14C-labelled leucine. The net rate of protein synthesis was found to be linear over 24 hours for mucosa from control subjects and patients with coeliac disease. Protein synthesis by mucosa from untreated coeliac patients was significantly greater than by control mucosa. Protein synthesis by treated gluten-sensitive coeliac mucosa was significantly less than that by untreated coeliac mucosa and did not differ from control mucosa. Protein synthesis by treated non-responsive coeliac mucosa was significantly less than untreated coeliac mucosa but greater than control mucosa. The differences in protein synthesis could not be accounted for by differences in the size of the enterocyte leucine pool. Analytical subcellular fractionation of cultured jejunal mucosa showed that most of the protein synthesised in vitro was found in the cytosol and endoplasmic reticulum-brush border fractions of the enterocyte.