Antioxidant effects on prostaglandin synthesis in rabbit kidney medulla slices.

Abstract

The effects of several classical antioxidants on prostaglandin synthesis were examined by using rabbit kidney medulla slices. The generation of prostaglandin E was stimulated slightly by the addition of 1,2-dimethoxyethane (10−3M) as a scavenger of hydroxyl radicals or 2,5-dimethylfuran (10−3M) as a scavenger of singlet oxygen (1.2-1.3 fold). Antioxidants such as sodium diethyldithiocarbamate (10−3M, SDDC), 2,6-di-tert-butylphenol (10−3M, DTBP) and N, N’-diphenyl-p-phenylenediamine (10−6M, DPPD) inhibited markedly the release of prostaglandin E. The inhibitory effect of antioxidants was dependent on their concentrations. These results indicate that antioxidants could either enhance or inhibit prostaglandin synthesis depending on the type of antioxidants. Moreover, we examined the effects of SDDC, DTBP and DPPD on the stimulation of prostaglandin production by exogenous arachidonic acid (10−4M). The arachidonic acid-induced stimulation was not blocked by SDDC and DPPD, but was blocked by DTBP. This suggests that SDDC and DPPD inhibit prostaglandin formation by interacting with phospholipase, and the inhibition of prostaglandin generation by DTBP could be mainly due to interaction with prostaglandin cyclooxygenase.