A long-term study of the effects of norethisterone on lipoprotein metabolism in menopausal women.

Long-term effects of the androgenic progestogen norethisterone on lipoprotein metabolism were studied by measuring lipoprotein concentrations in 21 women during one year on treatment for the relief of climacteric symptoms. There were significant reductions in total serum triglyceride (p less than 0.01), very low density lipoprotein (VLDL) cholesterol (p less than 0.01) and high density lipoprotein (HDL) cholesterol (p less than 0.001) after two months on treatment, all of which were still in evidence after one year. Low density lipoprotein (LDL) cholesterol levels climbed gradually becoming significantly higher than baseline after one year on treatment (p less than 0.01). Comparison of cholesterol concentrations in HDL subfractions in the one year treated subjects with those in a control group of untreated subjects suggests that the fall in HDL cholesterol is due to reductions in both the HDL2 and HDL3 fractions. We conclude that norethisterone adversely affects the important lipoprotein risk factors for coronary heart disease.