William's Medium E was developed by Williams and Gunn for the isolation and long term maintenance of adult rat liver epithelial cells. AL125 contains sodium bicarbonate and does not contain L-glutamine. William's Medium E was developed by Williams and Gunn for the isolation and long term maintenance of adult rat liver epithelial cells. The medium is a rich modification of William's medium D and was developed during studies performed to explore the possibilities of culturing adult liver cells on a long-term basis. AL125 contains sodium bicarbonate and does not contain L-glutamine.