Liver hypertrophy in winter flounder following exposure to experimentally oiled sediments.

1. Male winter flounder were exposed to sediments contaminated with Venezuelan crude oil in 3 laboratory experiments of 4-5 months duration. 2. Oil exposure resulted in significant increases in liver weight. This was particularly evident in fish weighing less than 400 g. 3. The enlarged livers of the oil-exposed flounder had reduced concentrations of DNA, protein, Na+ and Zn2+, and increased concentrations of lipid and phospholipid. 4. The reduced DNA and Na+ concentrations suggested liver hypertrophy rather than hyperplasia. 5. The increased phospholipid concentrations suggested growth of membrane structures such as endoplasmic reticulum.