Glucose and lactate utilization by the amygdala of male and female rats

Gonadal hormones appear to modulate brain energy metabolism, and morphological and functional sexual differences are found in the amygdaloid complex (AC) of rats. Our aim was to study the CO₂ production and lipid synthesis, measured by the rate of L-[U-¹⁴C]lactate or D-[U-¹⁴C]glucose utilization (in pmol.hr^–1.mg^–1), by AC slices in vitro of male and female rats. Lactate was more used than glucose as energy substrate (p < 0.01) but no sex-related difference was observed in glucose or lactate oxidation to CO₂ (p > 0.05) or on lipid synthesis obtained from both substrates (p > 0.05). In addition, there was no effect of the estrous cycle on lactate oxidation to CO₂ by the AC of females (p > 0.05). Based on the present data, it appears that the endogenous normal levels of gonadal hormones are not able to promote sex-related differences in the in vitro glucose or lactate utilization by the AC of rats.