The safety evaluation of phytosterol esters. Part 6. The comparative absorption and tissue distribution of phytosterols in the rat

• Published in: Food and chemical toxicology Vol. 38; no. 6; pp. 485 - 491
• Main Authors: Sanders, D.J, Minter, H.J, Howes, D, Hepburn, P.A
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-06-2000; New York, NY Elsevier Science
• Subjects: absorption; Animals; Autoradiography - methods; Biological and medical sciences; campesterol; cholesterol; Cholesterol - analogs & derivatives; Cholesterol - pharmacokinetics; Cholesterol - toxicity; Female; Food toxicology; Intestinal Absorption; Male; Medical sciences; phosphorimaging; phytosterol esters; phytosterols; Phytosterols - pharmacokinetics; Phytosterols - toxicity; plant sterols; Rats; Sitosterols - pharmacokinetics; Sitosterols - toxicity; Stigmasterol - pharmacokinetics; Stigmasterol - toxicity; Tissue Distribution; Toxicology; whole-body autoradiography; β-sitosterol; phosphorimaging; whole-body autoradiography; phytosterols; β-sitosterol; plant sterols; absorption; cholesterol; WBA=whole-body autoradiography; Rat; Toxicity; Rodentia; Oral administration; Lipids; Cholesterol; Sitosterol; Toxicokinetics; Vertebrata; Mammalia; Absorption; Animal; Phytosterol; Distribution; Plant origin; Pharmacokinetics; Food
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/S0278-6915(00)00021-1

As part of an extensive safety evaluation programme, a series of studies has been conducted to determine the fate of phytosterols in the rat. Rats were dosed by oral gavage with
14C-labelled samples of cholesterol, β-sitosterol or β-sitostanol or
3H-labelled samples of β-sitostanol, campesterol, campestanol or stigmasterol dissolved in sunflower seed oil. Urine and faeces were collected for up to 96 hours after dosing. There was no quantification of biliary excreted material in these studies. Animals were sacrificed and either prepared for whole body autoradiography or tissues and carcass remains were assayed for
14C or
3H. The overall absorption of phytosterols was low as judged by tissue and carcass levels of radioactivity. Elimination from the body was mainly in the faeces and was initially very rapid, but traces of material were still being excreted at 4 days after dosing. While total absorption of the phytosterols could not be fully quantified without biliary excretion data, it was clear that cholesterol was absorbed to the greatest extent (27% of the dose in females at 24 hours). Campesterol (13%) was absorbed more than β-sitosterol and stigmasterol (both 4%) which were absorbed more than β-sitostanol and campestanol (1–2%). The absorption of phytosterols was slightly greater in females than males. For each test material, the overall pattern of tissue distribution of radioactivity was similar, with the adrenal glands, ovaries and intestinal epithelia showing the highest levels and the longest retention of radioactivity.