Glutamine stimulates growth in rat cerebral endothelial cell culture

Endothelial cells were isolated from rat cerebral cortices using combined enzymatic digestions and Percoll gradient centrifugation. Primary cultures were subsequently grown on collagen-covered dishes in a medium containing 20% fetal calf serum and 0.6 mmol glutamine. The majority of cultures became confluent by day 7 or 8, but some could not reach confluence. The cells were fusiform in shape and exhibited immunoreactivity to factor VIII-related antigen and binding to the lectin Griffonia simplicifolia. Exposure of cultures to media containing 2.6 mmol glutamine resulted in accelerated growth (in cultures were confluent at days 3-4) and change in culture morphology, namely the formation of circular, cell-free areas. However, this treatment did not restore gamma-glutamyl transpeptidase activity that was lost during cultivation. As for other amino acids, asparagine was less potent, glycine and phenylalanine failed to mimic the glutamine effect. In summary, glutamine stimulates growth of cerebral endothelial cells in vitro and so it may supplement for other growth factors in the culture media.