AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 4 542-R550, Copyright © 1984 by American Physiological Society
Modulation of feeding by endogenous sugar acids acting as hunger or satiety factors
N. Shimizu, Y. Oomura and T. Sakata
Endogenous sugar acids, 3,4-dihydroxybutanoic acid (2-deoxytetronic acid,
2-DTA) and 2,4,5-trihydroxypentanoic acid (3-deoxypentonic acid, 3-DPA),
have been identified in the serum of fasted rats. Effects of these sugar
acids on rat feeding behavior and neuron activity were investigated.
Injections of 2-DTA (2.5 mumol) into the third cerebral ventricle of
chronic rats suppressed food intake and single-neuron activity in the
lateral hypothalamic area (LHA). Food consumption was reduced for 24 h,
even in 72-h food-deprived rats. The same amounts of 3-DPA elicited feeding
and increased LHA single-neuron activity with latencies of 6-8 min.
Electrophoretically applied 2-DTA significantly and specifically suppressed
activity of glucose-sensitive neurons in the LHA, whereas 3-DPA facilitated
the activity. Nonglucose-sensitive LHA neurons were not affected by these
sugar acids. The high correlation between modulation of feeding behavior
and changes in LHA neuron activity after injection of these sugar acids
suggested that 2-DTA may act as an endogenous satiety substance and 3-DPA
as a hunger substance. The effects may be mediated through
glucose-sensitive neurons in the LHA.
