Elevated glucose utilization in the subfornical organ during dehydration.
We review results from several rat models of dehydration in which increases in the rate of glucose utilization were found in the subfornical organ and in other cerebral structures participating in the regulation of thirst and fluid balance. During chronic saline ingestion, the simplest model of dehydration involving only plasma hypertonicity, glucose utilization in the subfornical organ was normal. In water-sated homozygous Brattleboro rats, in which plasma osmolality and levels of angiotensin II are increased, glucose metabolism in the subfornical organ was 44% higher than in water-sated Long-Evans rats. In a complex model of dehydration, chronic water deprivation which is associated with high levels of plasma osmolality, angiotensin II, and baroreceptor disinhibition, there was a 72% increase in subfornical organ glucose utilization. The results suggest that angiotensin II is an important stimulant of metabolism in the subfornical organ, and that converging stimuli have a synergistic effect on metabolic activity in this structure.
D000804:Angiotensin II / Q000008:administration & dosage; D000818:Animals; D002216:Captopril / Q000008:administration & dosage; D003681:Dehydration / Q000378:metabolism* / Q000503:physiopathology; D003847:Deoxyglucose / Q000378:metabolism; D004195:Disease Models, Animal; D005947:Glucose / Q000378:metabolism*; D007263:Infusions, Parenteral; D007275:Injections, Intravenous; D008297:Male; D009490:Neurosecretory Systems / Q000378:metabolism*; D051381:Rats; D011910:Rats, Brattleboro; D011919:Rats, Inbred Strains; D013356:Subfornical Organ / Q000378:metabolism* / Q000502:physiology; D013997:Time Factors
D000804:Angiotensin II; D003847:Deoxyglucose; D002216:Captopril; D005947:Glucose