Induction of heat‐shock proteins by glutamine The ‘feeding effect’

Publisher Website
Google Scholar
Abstract
Subconfluent, log‐phase Chinese hamster ovary cells induced the major heat‐shock proteins (hsp) when cells were refed, 40 hours after seeding. This method of inducing heat‐shock proteins was also obtained by refeeding with fresh serum‐free media, but not with media with a long shelf life or with media prepared without glutamine. It was observed that addition of glutamine alone to cultures at 40 hours post‐seeding induced heat‐shock proteins. Addition of ammonium chloride, however, had no discernible effect on heat‐shock protein synthesis. Northern blot analysis indicated that this phenomenon reflected an increase in the levels of message for the constitutive/inducible member of the hsp 70 family, but not the non‐constitutive member. To determine the effect of this induction on heat sensitivity, unfed and ‘heat‐shock‐induced’ refed cultures were heated at 45°C. No significant difference in cell survival was observed. Therefore glutamine is the necessary ingredient required for the induction of heat‐shock proteins and this method of inducing heat‐shock proteins does not alter heat sensitivity.