In recent years there has been a concerted effort to reduce the cholesterol content of the human diet. The hens egg is a major source of cholesterol in the diet, and many attempts have been made to reduce its cholesterol content. Genetic selection [1,2], changes to the diet  and the use of hypocholesterolaemic drugs [1,3,4,5,6] have all been investigated. While some relatively modest changes have been reported, the majority of these studies suggest that egg yolk cholesterol is relatively resistant to change. However, little explanation has been given to account for these findings.
Egg cholesterol is derived from the liver and transported to the developing oocyte within very low density lipoproteins (VLDL). These particles are also responsible for the transport of triacylglycerol to me egg. If egg cholesterol is to be reduced, men VLDL must be specifically depleted of cholesterol. In me present study we investigated the effects of a cholesterol synthesis inhibitor on plasma VLDL concentrations and egg cholesterol. The compound used was simvastatin, known to be a potent inhibitor of mammalian hepatic hydroxymethylglutaryl CoA (HMG CoA) reductase, an important enzyme in regulating cholesterol synthesis.