LATE EFFECTS OF EARLY NUTRITIONAL MANIPULATIONS

Effects of early neonatal interventions on metabolic parameters later in life (s.c. late effects) were studied in rats using two models; nam ely, (a) the effects of premature weaning and (b) the effects of ''die tary'' manipulations during the suckling period (s.c. small vs. large litters). (a) Premature weaning of rats caused an earlier degeneration of spermiogenesis and elevated plasma cholesterol levels in adult ani mals when compared to levels found in animals weaned 12 days later (on day 30 after birth). In adult rats, radioiodine uptake in thyroid gla nds was lower in the group weaned prematurely. Premature weaning was f ollowed by a decrease of corticosterone production in adrenal glands i n adult animals; in female adult prematurely weaned rats, an elevated response of adrenal cortex to stressors was observed. Several other st udies explored the ''immediate'' effects of early, premature weaning. (b) Early exposure to high fat diet evoked a hypercholesterolaemic res ponse in adulthood following brief exposure to HF diet. Rats from litt ers reduced to 3 or 4 pups per mother on postnatal day 3 exhibited 2 d ays later plasma levels of cholesterol higher than in rats raised in l arge litters of 8 or 14. The difference between small and large litter s was preserved for the whole lifespan of the animals. In adulthood, r ats from small litters were fatter and had higher levels of plasma cho lesterol and insulin. Other studies suggester that early dietary exper ience may regulate the pattern of drug metabolism in adult life. An in hibition of diurnal plasma corticosterone variation was found in rats overfed during the neonatal period and an increased stimulation of lip olysis by norepinephrine and lipogenesis by insulin was demonstrated i n neonatally underfed rats. Interesting studies were reported in longi tudinally studies in children: at the age of 9-12 year brest-fed child ren (for more than 6 months) had the highest cholesterol levels; on th e other hand significantly increased levels of APO B, Apo Al, ATH inde x and Apo/B Apo Al quotient (p<0.05) were found in the nonbreast-fed g roup (27 references).