Comparison of the effects of etomidate, thiopentone and propofol on cortisol synthesis.

The inhibitory effects of etomidate, thiopentone and propofol on basal and ACTH-stimulated cortisol synthesis by isolated bovine adrenocortical cells have been examined. Concentrations required for 50% inhibition of ACTH-stimulated cortisol output were 1.1 X 10(-4) mol litre-1 for propofol, 3 X 10(-5) mol litre-1 for thiopentone and 4.6 X 10(-1) mol litre-1 for etomidate. At concentrations likely to be achieved during anaesthesia, etomidate would block cortisol output by isolated cells, thiopentone might slightly reduce output and propofol would be unlikely to alter cortisol synthesis significantly.