Abstract
A new fatty liver model is described in which heredity plays a major role. A marked fatty liver develops when the homozygous mutant Zucker rat (ff or "fatty") is fed a semi-synthetic diet enriched in sucrose. Lean littermates do not develop fatty livers on this experimental diet. Even old ff rats do not develop fatty livers on chow; the experimental diet is required. The fatty liver is described, including light microscopic and preliminary electron microscopic observations.