Changes of enzymes involved in prostaglandin metabolism and prostaglandin binding proteins in rat brain during development and aging.

In the developing rat brain, the enzymatic formation of prostaglandin D2 from prostaglandin H2 increased 60-fold from day 12 of gestation to birth. The activity still rose gradually to the highest level (90 nmol/min/g wet tissue) at day 7 after birth. The activities of prostaglandin E2 and F2 alpha synthetases in rat brain were highest at gestational age 19 days (30 nmol/min/g wet tissue), respectively. The specific activity of NADP-dependent 15-hydroxy-prostaglandin D2 dehydrogenase in rat brain was highest at the earliest gestational age we examined (day 12 of gestation). The specific bindings of prostaglandin D2 and E2 to the crude mitochondrial fraction of rat brain were observed from day 16 of gestation and increased to day 7 after birth. Although the activities of the enzymes responsible for prostaglandin metabolism were unchanged postmaturationally, the maximal concentrations of the binding sites on the synaptic membrane for both prostaglandins D2 and E2 decreased with constant affinity to less than one-sixth with age from 1 week to 24 months after birth. These results indicate that prostaglandins may play important roles during maturation and aging in rat brain.