Abstract
We treated testicular cell lines Leydig TM3 and Sertoli TM4 with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and used two-dimensional electrophoresis to investigate the resulting protein alterations. Cells were cultured in a medium containing 10-5 to 10 nM TCDD for 4 hr, under which condition viability was not affected. Protein expression was compared semi-quantitatively by silver staining, by autoradiography of [35S] methionine-labeled proteins, and by anti-phosphotyrosine antibody. In TM3, 34 protein spots were altered by TCDD, 26 of which were increased and 8 of which were decreased; in TM4, the amount of total protein appeared to be reduced and 19 protein spots were altered by TCDD, 12 of which were increased and 7 of which were decreased. Four of these altered proteins were identified by N-terminal protein microsequencing and by a homology search against protein databases. Whereas a pyruvate dehydrogenase E1 beta subunit was decreased by TCDD exposure, ATP synthase beta chain, mitochondrial matrix protein P1 and 78 kDa glucose-regulated protein were relatively increased. The precise role of these proteins in TCDD toxicity remains to be determined, but the observed alterations suggest the proteins to be important in the effects of TCDD on testicular cells.
