Hydrocortisone effects on adhesion and glutamine synthetase specific activity during the cell cycle of cultured mouse teratoma cells

Previous studies of teratoma cells in batch culture demonstrated that glutamine synthetase (GS) specific activity was cell density dependent, increasing as the culture approached confluency. Other studies also showed that intercellular adhesion and GS specific activity increased in the presence of hydrocortisone. Confluency frequently reflects a non-cyclic cell population. Hence, in batch culture the increase in GS activity at confluency may be a consequence of the cells either leaving the cell cycle or coming into register at a given point in it, e.g. G1. Therefore it is desirable to determine if GS activity and adhesion are properties of non-cyclicing as well as actively growing populations. These studies were undertaken to determine if there is a relationship between intercellular adhesion and GS specific activity during the cell cycle and if hydrocortisone effects these parameters. To determine if increased cell adhesiveness and GS specific activity occur at specific times during the cell cycle, cell populations were synchronized with thymidine (3m.M) plus colcemid (5ug/ml). (See more in text.)