Sex-related glucose effects on responsiveness to brightness change in middle-aged rats

Unlike younger animals, middle-aged hooded rats showed no evidence of a tendency to enter first and spend time in the arm of a Y-maze that had changed in brightness between an exposure and a choice trial. When treated with 50 or 100 mg/kg D-glucose, female (but not male) middle-aged rats entered first the novel changed arm, whereas male (but not female) subjects repeatedly entered both arms more often and spent longer in them following glucose administration. The female-specific glucose effects on first entries of the novel arm may have been due to changes in attention, novelty preference or memory possibly arising from interactions with estrogen levels. It was suggested that the male-specific results for entries of both arms may have reflected females' lower sensitivity to glucose effects because of their higher baseline activity levels.