Direct effect of gossypol on TR-ST cells: perturbation of rhodamine 123 accumulation in mitochondria.
Gossypol has deleterious effects directly on TR-ST cells originating from a rat testicular tumor. Exposure of TR-ST cells to gossypol (5 micrograms/ml) decreases their rate of protein synthesis approximately 30% within 1 h and 65% by greater than 10 h, causes intracellular vacuolation, changes cell shape from cobblestone to a rounded conformation and inhibits cell proliferation. Yet, these gossypol-treated cells remain viable, as assessed by their ability to hydrolyze fluorescein diacetate. Gossypol also perturbs mitochondrial transmembrane potential in TR-ST cells, as demonstrated by marked changes in rhodamine 123 staining. Mitochondria of control TR-ST cells avidly accumulate rhodamine 123, but those in cells exposed to gossypol (greater than or equal to 5 micrograms/ml) for greater than 1 h fail to sequester the fluorochrome. Instead, the cell cytoplasm shows a light and diffuse staining with rhodamine 123. Rat spermatozoa show a similar response. Conversely, at concentrations of 20 micrograms/ml, gossypol has minimal effects on rhodamine 123 accumulation by primary cultures of hepatocytes and by rat spermatogenic cells, including primary spermatocytes and spermatids (Steps 1-12). Moreover, TR-ST cells exhibit reduced mitochondrial staining with gossypol at an ED50 of 7.6 micrograms/ml, while those for the nontesticular Rat-1, AnAn, 3T3 and PtK2 cell lines are 13.1, 21.5, 28.5 and 26.4 micrograms/ml, respectively.
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes; D006072:Gossypol / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology*; D014176:Protein Biosynthesis; D051381:Rats; D020112:Rhodamine 123; D012235:Rhodamines / Q000378:metabolism*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D013736:Testicular Neoplasms / Q000473:pathology / Q000503:physiopathology*; D014966:Xanthenes / Q000378:metabolism*
D005456:Fluorescent Dyes; D012235:Rhodamines; D014966:Xanthenes; D020112:Rhodamine 123; D006072:Gossypol