Mode of hypocholesterolemic action of S-methylmethionine (vitamin U) in mice.

S-Methylmethionine (vitamin U) markedly increased the fecal excretion of both 14C-bile acids and 14C-neutral sterols in 14C-cholesterol injected mice, and did not inhibit both intestinal absorption of 14C-cholesterol and biosynthesis of 14C-cholesterol from 14C-acetate in mice.