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 16α-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.
|Number of pages
|Proceedings of the National Academy of Sciences of the United States of America
|Published - 1989
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