Uptake and utilization of metabolites in specific brain sites relative to feeding status

Two experiments were conducted to assess potential alterations in fatty acid and glucose metabolism within specific brain sites in relation to the feeding status of the rat. An in vivo serial analysis of brain palmitate and glucose uptake demonstrated that hypothalamic uptake of these substrates was reciprocally altered with respect to satiety. Hypothalamic uptake of palmitate was increased by 300% and uptake of glucose was decreased by 30% in fasted compared with fed rats. Other regional differences were observed and discussed in the text. An in vitro analysis showed that hypothalamic fatty acid oxidation was affected by feeding status. The ventrolateral hypothalamus (VLH) of fasted rats had 45% greater rates of fatty acid oxidation than VLH of fed rats. No alterations were observed for VLH glucose oxidation and ventromedial hypothalamic glucose and fatty acid oxidation when comparing fed and fasted rats. Other brain sites did not show variance for glucose and fatty acid metabolism relative to feeding status. Fatty acid uptake and subsequent metabolism in the hypothalamus and other brain sites may be one component of food intake control and energy balance regulation.