Diurnal variation in ornithine decarboxylase activity of different brain regions of the rat.

Abstract The activity of ornithine decarboxylase (ODC) was studied in the brain of Sprague-Dawley male rats weighing 200–250 g. In this study, animals were maintained at a temperature of 21 ± 1°C and a 12:12 h light-dark cycle for a minimum of 3 weeks prior to any experimentation. Animals were sacrificed at 06.00 h and 18.00 h and the brain cerebral cortex, hypothalamus, amygdala, hippocampus, midbrain, pons, medulla oblongata and cerebellum were isolated and assayed for ODC activity. The data show significant diurnal variations ( P