PHOSPHOLIPID-COMPOSITION OF NEONATAL GUINEA-PIG LIVER AND PLASMA - EFFECT OF POSTNATAL FOOD RESTRICTION

Preterm guinea pigs were delivered on day 65 of gestation (term = 68 d ) and were allowed either free or restricted access to food for the su bsequent 48 h. Plasma phosphatidyl-choline (PC) concentration increase d postnatally from 190 (range 144-307) to 751 (426-1039) and 883 (758- 977) mu M for fed and starved pups, respectively. Plasma PC compositio n in both groups of pups was characterized by selective and equivalent relative increases to individual molecular species containing 18:0 at the sn-1 position. Hepatic PC concentration increased from 6.75 (5.41 -8.20) to 8.65 (6.54-10.63) and 9.23 (8.18-10.17) mu mol/g for fed and starved pups, respectively, and, under all conditions, hepatic PC mol ecular composition closely mirrored that of plasma PC. These results s upport the hypothesis that the molecular species composition of plasma PC for the guinea pig in the immediate postnatal period is determined largely by the composition of the hepatic PC pool destined for lipopr otein secretion. Hepatic PC composition and concentration of the starv ed neonatal guinea pig were maintained independently of any dietary nu trient intake, at the expense of mobilization of extra hepatic lipid r eserves. While this adaptive mechanism has inherent limited survival p otential in neonatal starvation, it has implications for studies measu ring plasma phospholipid fatty acid compositions as biochemical marker s of dietary fat intake in preterm infants.