TY - JOUR
T1 - Energy expenditure and body composition of chronically maintained decerebrate rats in the fed and fasted condition
AU - Harris, Ruth B.S.
AU - Kelso, Emily W.
AU - Flatt, William P.
AU - Bartness, Timothy J.
AU - Grill, Harvey J.
PY - 2006/3
Y1 - 2006/3
N2 - The contribution of the caudal brainstem to adaptation to starvation was tested using chronically maintained decerebrate (CD) and neurologically intact controls. All rats were gavage fed an amount of diet that maintained weight gain in controls. CD rats were subjected to a two-stage surgery to produce a complete transection of the neuroaxis at the mesodiencephalic juncture.One week later, the rats were housed in an indirect calorimeter, and 24 h energy expenditure was measured for 4 d.One half of each of the CD and control groups was then starved for 48 h. Fed CD rats maintained a lower body temperature (35 C), a similar energy expenditure per unit fat-free mass but an elevated respiratory quotient compared with controls. They gained less weight, had 20% less lean tissue, and had 60% more fat than controls. Circulating leptin, adiponectin, and insulin were elevated, glucose was normal, but testosterone was dramatically reduced. Responses to starvation were similar in CD and controls; they reduced energy expenditure, decreased respiratory quotient, indicating lipid utilization, defended body temperature, mobilized fat, decreased serum leptin and insulin, and regulated plasma glucose. These data clearly demonstrate that the isolated caudal brainstem is sufficient to mediate many aspects of the energetic response to starvation. In intact animals, these responses may be refined by a contribution by more rostral brain areas or by communication between fore- and hind-brain. In the absence of communication from the fore-brain, the caudal brainstem is inadequate for maintenance of testosterone levels or lean tissue in fed or fasted animals.
AB - The contribution of the caudal brainstem to adaptation to starvation was tested using chronically maintained decerebrate (CD) and neurologically intact controls. All rats were gavage fed an amount of diet that maintained weight gain in controls. CD rats were subjected to a two-stage surgery to produce a complete transection of the neuroaxis at the mesodiencephalic juncture.One week later, the rats were housed in an indirect calorimeter, and 24 h energy expenditure was measured for 4 d.One half of each of the CD and control groups was then starved for 48 h. Fed CD rats maintained a lower body temperature (35 C), a similar energy expenditure per unit fat-free mass but an elevated respiratory quotient compared with controls. They gained less weight, had 20% less lean tissue, and had 60% more fat than controls. Circulating leptin, adiponectin, and insulin were elevated, glucose was normal, but testosterone was dramatically reduced. Responses to starvation were similar in CD and controls; they reduced energy expenditure, decreased respiratory quotient, indicating lipid utilization, defended body temperature, mobilized fat, decreased serum leptin and insulin, and regulated plasma glucose. These data clearly demonstrate that the isolated caudal brainstem is sufficient to mediate many aspects of the energetic response to starvation. In intact animals, these responses may be refined by a contribution by more rostral brain areas or by communication between fore- and hind-brain. In the absence of communication from the fore-brain, the caudal brainstem is inadequate for maintenance of testosterone levels or lean tissue in fed or fasted animals.
UR - http://www.scopus.com/inward/record.url?scp=32644441245&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=32644441245&partnerID=8YFLogxK
U2 - 10.1210/en.2005-1156
DO - 10.1210/en.2005-1156
M3 - Article
C2 - 16357041
AN - SCOPUS:32644441245
SN - 0013-7227
VL - 147
SP - 1365
EP - 1376
JO - Endocrinology
JF - Endocrinology
IS - 3
ER -