ONTOGENY OF GROUP-II PHOSPHOLIPASE A(2) GENE-EXPRESSION IN RAT STOMACH AND ILEUM

Phospholipase A(2) (PLA(2)) activity is important in the gastrointesti nal tract, but detailed information about the different PLA(2) isoenzy mes present in the gastrointestinal mucosa is yet lacking. In the pres ent study, we have investigated the postnatal development of group II phospholipase A(2) (PLA(2) II) gene expression in the forestomach, gla ndular stomach, and ileum of neonatal rats. The amounts of PLA(2) II m RNA in the glandular stomach increased with age in 15- to 60-day-old r ats (i.e. adult animals), whereas the PLA(2) II gene expression in the forestomach and ileum increased between 15 and 21 days, but not betwe en 21 days and adults. The PLA(2) II gene expression of all three tiss ues investigated was induced precociously in rats treated with cortiso ne acetate at days 12, 13 and 14. Taken together, the results indicate that (1) the ontogeny of rat glandular stomach PLA(2) II gene express ion is similar to the ontogeny previously described for rat glandular stomach group I PLA(2); (2) the ontogeny of rat forestomach, glandular stomach and ileal PLA(2) II gene expression is related to the glucoco rticoid-induced maturation of the rat gastrointestinal tract during th e neonatal period, and (3) the ontogeny of PLA(2) II gene expression i s different in the glandular stomach compared to the ileum and foresto mach, which may indicate a different physiological role of PLA(2) II, and/or a different postnatal maturation, in the glandular stomach.