AJP - Regulatory, Integrative and Comparative Physiology, Vol 262, Issue 1 14-R19, Copyright © 1992 by American Physiological Society
Quantitative changes in long-chain fatty acids during fetal and early postnatal development in rats
S. C. Cunnane and Z. Y. Chen
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.
The quantitative importance of triacylglycerol as a source of total
essential fatty acids during early postnatal development is reported in the
accompanying article. Our objective here was to measure the quantitative
changes in individual long-chain fatty acids in specific lipid classes of
the carcass, liver, and brain of the developing rat mainly to describe the
relative accumulation of long-chain vs. precursor fatty acids. Fatty acids
in carcass phosphatidylcholine (micrograms/g) were lower at fetal days
18-21 than at either fetal day 15 or postnatal days +3 to +9. Individual
long-chain fatty acids in liver phosphatidylcholine and
phosphatidylethanolamine increased markedly by day +3 postnatally, whereas
in brain phosphatidylethanolamine, the postnatal increase was delayed to
between days +6 and +9. Fatty acids in carcass and liver triacylglycerols
increased quantitatively by 10- to 300-fold from fetal day 21 to postnatal
day +3 with amounts of both arachidonic and docosahexaenoic acid equaling
linoleic acid. The ratios of linoleic and alpha-linolenic acids to
respective long-chain products were significantly higher in
triacylglycerols, whereas that of stearic to oleic acid was higher in
phospholipids. We conclude that, during early postnatal life, oleic,
linoleic, and alpha-linolenic acids are required in quantitatively greater
amounts in triacylglycerols, whereas stearic acid and long-chain essential
fatty acids are required in phospholipids.
