The effect of estrogen administration to cultured Armenian hamster was stud
ied. Isolated Armenian hamster hepatocytes were cultured in RPMI medium sup
plemented with beta-estradiol (E-2) beta-estradiol treatment for 24-48 hr i
nduced cytoplasmic inclusion bodies which by immunocytochemistry were posit
ive for cytokeratin (CK) 8, CK 18, and ubiquitin but negative for CK 7 and
CK 19. These inclusion bodies appeared as filamentous tangles or amorphous
aggregates when observed by electron microscopy. F-actin, tubulin, and desm
osomes were not influenced by the presence of the inclusion bodies. Additio
n of ethanol to culture medium increased the incidence of the inclusion for
mation. In combination with 0.5% ethanol 1 mu M of E-2 induced five to six
times more inclusion bodies, while the number of inclusion bodies decreased
when epidermal growth factor (EGF) was added to the medium in combination
with E-2. This reduction effect was nullified by treatment with anti-EGF re
ceptor antibody. These findings suggest that E-2 treatment to Armenian hams
ter hepatocytes in vitro induces Mallory body-like inclusions whose inciden
ce can be influenced by addition of ethanol or EGF to the culture medium. C
ell Motil. Cytoskeleton 43:35-42, 1999. (C) 1999 Wiley-Liss, Inc.