0.2, 0.4, 0.8 and 1.6 mg/day for 4 weeks

Adrenal explants, obtained from patients undergoing expanded nephrectomy for kidney cancer, were immediately transported to the laboratory in Dulbecco Modified Eagle’s Medium (DMBM). After dissection and preincubation in DMEM at 20 C, adrenocortical fragments consisting of both glomerulosa and fasciculata zones were mixed with Bio-Gel P2 and transferred into perifusion chambers. Each perifusion column contained approximately 100 mg wet tissue: The perifusion chambers were supplied with DMEM at a constant flow rate (260 mkL/min). The pH (7.4) and temperature (37 C) were kept constant throughout the experiment. The perifusion medium was continuously gassed with a 95% O2-5% CO2 mixture. The tissues were allowed to stabilize for 2 h before zacopride was administered. Zacopride was dissolved in gassed DMEM and infused for 20 min into the perifusion chambers at the same flow rate as DMEM alone by means of a multichannel peristaltic pump. Fractions of the effluent perifusate were collected every 5 min and immediately frozen until assay. Aldosterone and cortisol concentrations were determined by RIA.