Open AccessMechanism of inhibition of growth of 3T3-L1 fibroblasts and their differentiation to adipocytes by dehydroepiandrosterone and related steroids: role of glucose-6-phosphate dehydrogenase.
Author(s) -
Lisa M. Shantz,
Paul Talalay,
Gary Gordon
Publication year - 1989
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.86.10.3852
Subject(s) - pentose phosphate pathway , dehydroepiandrosterone , glucose 6 phosphate dehydrogenase , dehydrogenase , endocrinology , chemistry , intracellular , medicine , cellular differentiation , steroid , biochemistry , phosphogluconate dehydrogenase , glycolysis , biology , enzyme , androgen , hormone , gene
Dehydroepiandrosterone (DHEA) and certain structural analogues block the differentiation of 3T3-L1 mouse embryo fibroblasts to adipocytes. These steroids also are potent uncompetitive inhibitors of mammalian glucose-6-phosphate dehydrogenases (G6PDs). We provide direct evidence that treatment of the 3T3-L1 cells with DHEA and its analogues results in intracellular inhibition of G6PD, which is associated with the block of differentiation: (i) Levels of 6-phosphogluconate and other products of the pentose phosphate pathway are decreased; (ii) the magnitude of these decreases depends on the potency of steroids as inhibitors of G6PD and on concentration and duration of exposure, and it is accompanied by a proportionate block of differentiation; (iii) in cells exposed to 16 alpha-bromoepiandrosterone (a more potent inhibitor of G6PD than DHEA) at concentrations that block differentiation, introduction of exogenous 6-phosphogluconate in liposomes raises the levels of 6-phosphogluconate and other products of the pentose phosphate pathway and partially relieves the steroid block of cell growth and differentiation.