This study assessed sex differences in stable metabolites of nitric oxide and major enzymes involved in antioxidant defense in various regions of rat brain. Nitrite/nitrate levels and activities of superoxide dismutase and catalase were determined in cortex, hippocampus, corpus striatum, midbrain and cerebellum of adult male and female Sprague-Dawley rats. Nitrite/nitrate levels were significantly higher in the cortex and the hippocampus of male than female rats, while catalase activity was higher in the cortex of females than in males. These sex differences may have significant effects on brain function in health and disease.

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Summary:The aim of this study was to observe membrane injury and to investigate the mechanism of antioxidant defence Systems against acute ethanol toxicity. Erythrocyte Superoxide dismutase and Na" 1 ", K^-ATPase activities were significantly decreased and catalase levels were significantly increased one hour after ethanol intoxication of male swiss albino rats. These data demonstrated that Superoxide dismutase and catalase are susceptible to lipid peroxidation and that these enzymes protect tissues from free radicals. The possible mechanism involved in Na + , K + -ATPase and Ca 2 " 1 "-ATPase Inhibition are discussed in relation to the development of ethanol toxicity and the role of lipid peroxidative processes.

Abnormal glutamate metabolism is implied in the pathogenesis of Amyotrophic Lateral Sclerosis (ALS) and cerebrospinal fluid (CSF) glutamate levels appear to be elevated. Since nitric oxide (NO) inhibits glutamate transport, excessive amounts of nitric oxide could underlie the glutamate induced neurotoxicity in ALS. Stable metabolites of NO (NO2- + NO3-) levels were determined in serum and CSF of sporadic ALS patients and control subjects. NO2- + NO3- levels were higher in ALS, in males and in serum samples compared to controls, females and CSF, respectively. Furthermore, while the difference between serum and CSF NO2- + NO3- levels was significant in males (higher in serum) no such difference was observed in females. Our results suggest that nitric oxide may be involved in the pathogenesis of ALS directly or indirectly and in a sexually dimorphic manner.