AJP - Regulatory, Integrative and Comparative Physiology, Vol 243, Issue 3 223-R228, Copyright © 1982 by American Physiological Society
Incorporation of polyunsaturated fatty acids into lipids of rainbow trout hepatocytes
P. A. Sellner and J. R. Hazel
Hepatocytes from 5- or 20 degrees C-acclimated rainbow trout (Salmo
gairdneri) were incubated with [1-14C]oleic, -linoleic, or -linolenic acid.
Both acclimation groups demonstrated greater incorporation of derivatives
from linolenic and linoleic acids into phospholipids when assayed at 5 and
20 degrees C; few derivatives of oleic acid were formed. Cells from
cold-acclimated trout, when assayed at 5 degrees C with linolenic acid,
incorporated a large proportion of radioactivity into free fatty acids.
Analysis of each lipid fraction revealed a relatively specific
incorporation of certain fatty acids. For example, "dead end" elongation
products of the three substrates were preferentially incorporated into
neutral lipids, while delta 6 desaturation products of the three acids were
retained in the free fatty acid fraction. Twenty-carbon acid derivatives of
linoleic and linolenic acids were directed into the phospholipid fraction.
Incorporation of the delta 5 desaturation products was temperature
sensitive in cells from cold-acclimated but not warm-acclimated trout. The
results suggest that selectivity of incorporation of specific fatty acids
into phospholipids may be of importance in restructuring membranes of
poikilotherms during thermal adaptation.
