Dietary effect of yeast extract or glutathione on lipid metabolism and immune function of Sprague-Dawley rats

Dietary effect of yeast extract YH (YH) and glutathione on lipid metabolism and immune function of Sprague-Dawley rats was examined. Dietary effect of these diets was small on growth and tissue weights, as well as the effect on serum levels of cholesterol, triglycerides, phospholipids and tribarbituric acid reactive substances. On the other hand, LTB4-releasing activity of peritoneal exudate cells was significantly lower in the rats fed 10% YH diet than the rats fed control or 1% YH diet. In the rats fed 0.01% GSH diet, enough number of peritoneal exudate cells was not recovered. In addition, YH and GSH feeding slightly decreased the levels of serum IgA, IgG and IgM, as well as the productivities of these antibodies in spleen lymphocytes. These results suggest that YH feeding affects rat immune functions such as eicosanoid and immunoglobulin production.