Previously, the function of this protein, selenoprotein P, was unknown, although it was believed to play a role as an antioxidant and to transport selenium throughout the body.

Dietary selenium is essential for normal sperm development and male fertility. Selenoprotein P, or SEPP1, carries about 60 percent of the selenium in blood plasma.

To understand the physiological function of SEPP1 in the testes and epididymis of mammals, a team of scientists at Vanderbilt University in Nashville studied male mice that lack the gene to produce SEPP1. These genetically altered males have levels of selenium in the testis that are less than 10 percent of those in control mice, and they are generally infertile.

The research team, headed by Dr. Gary E. Olson, found that the mutant male mice lacking SEPP1 develop sperm with defective tails, similar to the sperm produced by unaltered male mice fed a low-selenium diet.

Furthermore, the mutant mice do not recover normal sperm production after prolonged feeding on a diet supplemented with high levels of selenium, and they remain infertile. Thus, even selenium supplements could not overcome the need for SEPP1 to facilitate normal sperm development.

These findings, according to Olson and colleagues, strongly indicate that SEPP1 is the source of the selenium needed for development of normal sperm and for male mice to maintain their fertility.

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Patients entered the study with LDL-cholesterol levels between 130 mg/dL and 250 mg/dL. More than half of the patients taking Lipitor at 10 mg doses achieved LDL-cholesterol levels of 100 mg/dL or lower.

TNT is an investigator-led trial coordinated by an independent steering committee and was funded by Pfizer. The study enrolled men and women between 35 and 75 years of age in 14 countries.

"In addition to providing outstanding benefits at the lowest and highest doses of Lipitor in the TNT study, it's important to note that patients achieved these benefits safely," Dr. Feczko said. "This is critical new information that potentially could have a significant impact on how physicians approach the treatment of heart disease."

Coronary heart disease is the leading cause of death in the United States, and the majority of Americans with elevated cholesterol, a leading risk factor for heart attacks, are not at their recommended goal levels. Updated guidelines issued by the National Cholesterol Education Program confirm the added benefit of prescribing cholesterol-lowering medication like Lipitor, along with diet modification and exercise, to patients at risk for cardiovascular disease. In addition, the NCEP panel has recommended an LDL- cholesterol level of less than 100 mg/dL as the goal of therapy for patients at high risk of coronary heart disease.

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