H. Segner et al., CULTURED TROUT LIVER-CELLS - UTILIZATION OF SUBSTRATES AND RESPONSE TO HORMONES, In vitro cellular & developmental biology. Animal, 30A(5), 1994, pp. 306-311
The characterization of a recently established system for the short-te
rm culture of rainbow trout (Oncorhynchus mykiss) liver cells in chemi
cally defined medium has been extended to studies on the metabolic com
petence of the cells and the characterization of their response to hor
mones. Three areas of metabolism have been addressed: a) the utilizati
on of the exogenously added substrates fructose, lactate, glucose, dih
ydroxyacetone, and glycerol for glucose and lactate formation; b) the
effects of the pancreatic hormones insulin and glucagon on cellular gl
ucose formation, lactate formation, and fatty acid synthesis; and c) t
he effects of insulin and dexamethasone on the estradiol-dependent pro
duction of vitellogenin. Incubation of trout liver cells with fructose
, lactate, glucose, dihydroxyacetone, or glycerol resulted in enhanced
rates of cellular glucose and lactate production. Substrate-induced e
ffects usually were more clearly expressed after extended (20 h) than
after acute (5 h) culture periods. Addition of the hormones insulin or
glucagon caused dose-dependent alterations in the flux of substrates
to glucose and lactate. Rates of de novo synthesis of fatty acids from
[C-14]acetate were stimulated by insulin and inhibited by glucagon du
ring acute and extended incubation periods. Treatment of liver cells i
solated from male trout for 72 h with estradiol induced vitellogenin p
roduction and secretion into the medium. However, the addition of insu
lin or dexamethasone drastically reduced this estrogen-induced vitello
genesis. These results indicate that trout liver cells cultured in def
ined medium maintain central metabolic pathways, including glycolysis,
gluconeogenesis, lipogenesis, and vitellogenesis as well as their res
ponsiveness to various hormones, for at least 72 h. This cell culture
system should provide an excellent model to further characterize metab
olic processes in fish liver.