Differential effects of probenecid on the levels of endogenous PGF2α and TXB2 in brain cortex

Probenecid in single or repeated doses does not modify levels of PGF_2α and TXB₂ in rat brain cortex. After administration of subconvulsant dose of pentamethylene tetrazone (PMT) PGF_2α increases sharply and rapidly declines subsequently, whereas the elevation of TXB₂ is smaller but of longer duration. After probenecid pretreatment PGF_2α levels do not decline up to 30 minutes after the initial peak and are still elevated after 60 minutes. Levels of TXB₂ tend to be reduced after pretreatment. Differences in transport process or in biosynthetic compartments for these arachidonic acid (AA) metabolites may account for the observed data.