Ontogeny of group II phospholipase A2 gene expression in rat stomach and ileum.

Phospholipase A2 (PLA2) activity is important in the gastrointestinal tract, but detailed information about the different PLA2 isoenzymes present in the gastrointestinal mucosa is yet lacking. In the present study, we have investigated the postnatal development of group II phospholipase A2 (PLA2 II) gene expression in the forestomach, glandular stomach, and ileum of neonatal rats. The amounts of PLA2 II mRNA in the glandular stomach increased with age in 15- to 60-day-old rats (i.e. adult animals), whereas the PLA2 II gene expression in the forestomach and ileum increased between 15 and 21 days, but not between 21 days and adults. The PLA2 II gene expression of all three tissues investigated was induced precociously in rats treated with cortisone acetate at days 12, 13 and 14. Taken together, the results indicate that (1) the ontogeny of rat glandular stomach PLA2 II gene expression is similar to the ontogeny previously described for rat glandular stomach group I PLA2; (2) the ontogeny of rat forestomach, glandular stomach and ileal PLA2 II gene expression is related to the glucocorticoid-induced maturation of the rat gastrointestinal tract during the neonatal period, and (3) the ontogeny of PLA2 II gene expression is different in the glandular stomach compared to the ileum and forestomach, which may indicate a different physiological role of PLA2 II, and/or a different postnatal maturation, in the glandular stomach.