[Inventions for preservation of hormonal function in long-term culture of human functioning pituitary adenoma]

This study was designed to establish in vitro model systems in human hormone-producing pituitary adenomas that are analogous to the in vivo cellular environment. Mechanically dispersed cells composed of single cells and aggregates from 6 pituitary adenomas (3 GH producing adenomas and 3 prolactinomas) were cultured on microporous membrane cell culture inserts (Millicell-CM) coated with Basement Membrane Matrigel for up to 6 months. Growth hormone or prolactin in the medium was measured during the culture, and morphological feature in vitro was also compared with that of the original tumor at intervals. Not only single cells but also large aggregated cells which usually float in the medium when seeded on conventional plastic, were flattened and firmly attached to coated microporous membrane under the control of medium volume in culture. In both type adenomas, especially prolactinomas, surviving aggregated adenoma cells revealed preserved hormone activity and no dedifferentiation of cell characteristics after 6 months in culture. Particularly during the first 2 months in culture, close similarity existed between in vivo and in vitro conditions with regard to cell morphology and hormone release. These results indicate that this new culture method may further aid the investigation of in vitro cellular structure and function in human pituitary adenomas under conditions which closely mimic the in vivo cellular environment.