Distribution and metabolism of leukotriene C₄ after cisternal injection in guinea pigs

Following cisternal injection of [³H₈]LTC₄ into guinea pigs, leukotriene metabolites were identified in the brain, cerebellum, perilymph, blood, liver and kidneys. LTC₄ was metabolized into LTD₄ and LTE₄ in the cerebrospinal fluid and LTE₄ was transported into the blood for general circulation and uptake into the liver and kidneys. The excretion of LTE₄ from CNS to blood seemed to be the rate-limiting step in the elimination of leukotrienes from the body. Leukotrienes were also transported into the perilymph. The conversion of LTC₄ into LTD₄ and LTE₄ was lower in perilymph as compared to the cerebrospinal fluid, suggesting a rate limiting function of the cochlear aqueduct that can be defined as a cerebrospinal fluid-labyrinth barrier.