Gender difference in lipopolysaccharide‐induced anorexia in mice

Gender and vitamin C (ascorbate) may affect outcomes in septic illness after bacterial infection. We hypothesized that gender influences the anorexia and ascorbate responses elicited by E. coli lipopolysaccharide (LPS). Mice were maintained in a specific pathogen‐free facility, with access to irradiation‐sterilized PicoLab Mouse Chow 20 and autoclaved water, and were used for experiments when 10–11 wks old. Food intake was monitored for 1‐wk before and 20 h after injection of non‐lethal dose of LPS (5 mg/kg ip 1 h prior to 12 h dark cycle). Food intake before LPS injection was lower in females than in males. LPS decreased food intake but there was an interaction between LPS and gender, since food intake after LPS was higher in females than in males. The same LPS‐gender interaction on food intake was observed when control mice were saline‐injected or uninjected. Thus, female gender had less inhibitory effect of LPS on food intake. When analyzed at 20 h after injection of LPS or saline vehicle, females showed LPS‐induced increases in the ascorbate concentrations in liver and adrenal glands that were similar to those we have reported for males (J Nutr 135:2411–6, 2005). Adrenal ascorbate concentration was higher in females than males whether the mice were uninjected, saline‐injected or LPS‐injected. Slc23a2+/ − mice, which are deficient in the ascorbate transporter SVCT2, had lower ascorbate concentration in several tissues (J Nutr 134: 2216–21, 2004) and adrenal gland. However, LPS and gender had similar effects on food intake and ascorbate levels in the Slc23a2+/ − mice as in the wild‐type mice. In conclusion, these results supported a gender difference in the anorexia response but not the ascorbate response to LPS.