Further studies of the effects of an anovulatory drug on lipid metabolism in the rat.

The effect of various levels of the oral contraceptive drug, Enovid E, on serum and liver lipid levels of adult female rats has been investigated. Doses ranging from 0.052 to 1.04 mg/day have been employed in rats fed control or cholesterol-containing diets. It has been confirmed that after administration of even low, physiological doses of the drug, esterified cholesterol in serum and adrenals decreases rapidly while at the same time it accumulates in the liver; cholesteryl oleate is increased while the relative amount of cholesteryl arachidonate is reduced. Serum phospholipids also are decreased; the alpha/beta lipoprotein ratio is significantly reduced due to the decrease of alpha-lipoproteins. Most of these changes also occur in cholesterol-fed rats. The observed effects are not related to a decreased food intake.