Distribution of phytosterols in plasma and liver of rats nourished by different routes and effects on liver function

Phytosterols may lead to parenteral nutrition-associated cholestasis. We planned this study to quantify plasma and liver phytosterols and relate them to liver histology in rats receiving different lipid emulsions. Plasma phytosterols were quantified by gas chromatography-mass spectrometry in 30 inbred rats divided into 6 groups receiving total parenteral nutrition with soybean oil, soy+glutamine, olive oil, structured triglycerides, soy enteral formula, or chow. Hepatic phytosterols and cholesterol oxidation products were determined by gas chromatography-flame ionization. Data were related to liver histology. Groups on total parenteral nutrition with soy and olive oil had the highest plasma sitosterol levels, while those receiving soy or soy+glutamine had more stigmasterol (p=0.0013). These last 2 groups stored high quantities of hepatic campesterol, sitosterol, and stigmasterol. Hepatic cholesterol oxidation products, similarly represented across groups, tripled in rats receiving structured triglycerides. Across groups, liver specimens were normal. Phytosterols seem to accumulate more in the liver, particularly in rats on total parenteral nutrition with soy or soy+glutamine. However, the liver was not damaged by short-term infusion of different phytosterols. It may be that free movement and the lack of lipophilic drugs protected the animals.