Long-term induced effects by only one treatment with ketoconazole on rat tumoral pituitary cells (GH3/B6 strains)

Ketoconazole, an imidazole is a powerful antimycotic that has recently been used in the treatment of endocrinological and lipid metabolism disorders as well as in anti-cancer chemotherapy. When rat mammosomatotropic cells are treated for 30 hrs., this drug produces different effects depending on whether cells are normal or tumoral (GH3/B6). A dose of 10 microM had no effect in normal cells, however, in tumoral cells it had dramatic effects: (i) 50% of the cells are killed and those which survive no longer proliferate and they secrete GH but not PRL; (ii) they respond to GHRH in a dose-dependent manner, while normal cells do not under similar culture conditions; (iii) the lipid composition of the membrane is modified as indicated by the increase in arachidonic acid turn-over and the dramatic change in the distribution of its metabolites. For the moment we cannot explain these data.