AJP - Regulatory, Integrative and Comparative Physiology, Vol 262, Issue 1 8-13, Copyright © 1992 by American Physiological Society
Triacylglycerol: an important pool of essential fatty acids during early postnatal development in rats
S. C. Cunnane and Z. Y. Chen
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.
Developmental changes in the content and composition of major organ lipid
pools are not well known. Our objective was to assess quantitatively the
changes in lipids, particularly those containing long-chain fatty acids, in
the placenta and the brain, liver, and carcass of the fetal and suckling
rat. Pregnant dams were killed at days 15, 18, and 21 (term) of pregnancy
and the placentas and fetuses removed and analyzed; suckling rats were
killed at days +3, +6, and +9 of lactation. Whereas the long-chain fatty
acid content of the phospholipids (mg/g) of the fetal or suckling rat
remained relatively constant from day 18 of pregnancy to day +9 of
lactation, long-chain fatty acids in triacylglycerols increased from
prenatal values by 10- to 12-fold during the first 9 postnatal days.
Prenatally, triacylglycerol accounted for no more than 32% of total whole
body essential fatty acids (day 21), but postnatally this increased to
81-88%. From day 21 to day +9, the proportion of n-6 and n-3 essential
fatty acids within the total triacylglycerol pool of the suckling rat
increased 71 and 317%, respectively. We conclude that in the suckling rat,
triacylglycerol is quantitatively the most important source of essential
fatty acids during at least the first 9 days of life.
