Paradoxical effects of the anti-androgen cyproterone acetate on lipid and lipoprotein metabolism.

The effects on fasting serum lipids of the potent anti-androgen, cyproterone acetate (CA) and the oestrogen, ethinyl oestradiol (EO) given both alone and in combination were examined in women acting as their own controls. Cyproterone acetate alone caused significant reductions in total cholesterol, high density lipoprotein subfraction 2 cholesterol (HDL2) and low density lipoprotein cholesterol (LDL). Ethinyl oestradiol alone significantly increased triglycerides, HDL and HDL2 and reduced LDL, and there was also a significant increase in the HDL/LDL and HDL2/LDL ratios. The two steroids were administered in combination according to a reverse sequential regime. The 28-day treatment cycle thus included Phase A during which both drugs were given followed by Phase B when EO alone was given. Triglycerides rose significantly in Phases A and B to the same extent as for the group taking EO alone. High density lipoprotein cholesterol was unchanged but HDL2 was reduced in both phases and this effect could not be overcome by increasing the dose of oestrogen. Low density lipoprotein cholesterol fell and the HDL/LDL ratio rose during the two Phases and these changes were significant during Phase A. The effects of EO demonstrated in this study are consistent with previous reports. Cyproterone acetate, however, has properties conventionally ascribed to both synthetic androgens (e.g. lowering of HDL2) and oestrogens (e.g. lowering of LDL). The limitations of the terms androgenic and oestrogenic activity in relation to their conventional associations with changes in lipid and lipoprotein levels are discussed.