['Recently, it was reported that treatment with adrenocorticotrophic hormone (ACTH) has a strong lipid-lowering effect in healthy individuals. The mechanism behind this has not been established. The aim of the present investigation was to study the effect of ACTH on the plasma lipoprotein pattern in patients treated with a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor.', 'The ACTH treatment was given to 10 patients who were on long-term treatment with simvastatin 40 mg daily. ACTHI-24 was administered at the dose of 1 mg daily for four consecutive days. Blood samples for analyses of lipids, lipoproteins and apolipoproteins were collected before and after treatment. Second baseline was obtained 2 weeks after the end of treatment.', 'The serum concentrations of cholesterol, triglycerides, low density lipoprotein (LDL) cholesterol, apolipoprotein B and lipoprotein(a) fell significantly by 16, 23, 23, 10 and 38%, respectively. The serum apolipoprotein E concentration increased significantly by 39%; the fraction that was not associated with apolipoprotein B increased by 47% whereas the fraction that was did not change significantly. There were no changes in the serum concentrations of high density lipoprotein (HDL) cholesterol and apolipoprotein AI. At the second baseline, the lipid variables had generally returned to previous levels.'] Does adrenocorticotrophic hormone exert marked lipid-lowering effects in simvastatin-treated patients?