title: The role of the Crabtree effect and an endogenous fuel in the energy metabolism of resting and proliferating thymocytes.
abstract: Rat thymocytes have been used to characterize the changes in energy metabolism that occur as cells undergo a resting/proliferation transition. In the resting state, anaerobic ATP production accounts for only 4% of ATP turnover. The remainder is fueled by the oxidation of a mixture of an unidentified endogenous fuel (62%), glucose (18%) and glutamine (16%). 48 h after mitogen stimulation, the ATP turnover has increased twofold. In these proliferating cells, glucose inhibits oxygen consumption by 58%, indicating a profound Crabtree effect which is not present in resting cells. Consequently, proliferating cells, in the presence of glucose and glutamine, fuel the majority (61%) of ATP turnover anaerobically, producing lactate from glucose. The development of a Crabtree effect may be the result of the 8-10-fold increase in glycolytic enzyme activities which occurs with proliferation. Possible advantages of such a proliferative metabolism are a sparing of endogenous fuel, and a minimizing of oxidative metabolism, with its concurrent production of free radicals.
authors.affiliation: Institute of Biochemistry, Medical Faculty, University of Erlangen-Nürnberg, Federal Republic of Germany.
authors.forename: M
authors.initials: M
authors.lastname: Guppy
authors.forename: E
authors.initials: E
authors.lastname: Greiner
authors.forename: K
authors.initials: K
authors.lastname: Brand
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004734:Energy Metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D008213:Lymphocyte Activation; D010101:Oxygen Consumption / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013601:T-Lymphocytes / Q000378:metabolism*
chemical_list: D000255:Adenosine Triphosphate; D005947:Glucose