To further evaluate the effect of AC18, AC20 and AC22 on cellular viability, we performed MTT assays, in which the effect of each of these compounds on cell proliferation was compared to that of untreated control cells, or cells treated with either the negative AC1 TZD compound, or 5 μM rosiglitazone, a potent oral antidiabetic drug, whose inhibitory role on cell viability has been reported in vitro, in rat prolactin-secreting pituitary tumor cells (Gruszka, Kunert-Radek & Pawlikowski, 2005). The gene discussed is PRL; the disease is pituitary tumor.