AJP - Regulatory, Integrative and Comparative Physiology, Vol 256, Issue 2 366-R370, Copyright © 1989 by American Physiological Society
Stereospecific feeding modulation by endogenous organic acid gamma-lactone in rats
T. Sakata, K. Terada, K. Arase, K. Fujimoto, Y. Oomura, N. Okukado and O. Uchikawa
Department of Internal Medicine I, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Stereospecificity of 3,4-dihydroxybutanoic acid gamma-lactone (3,4-DB) and
2,4,5-trihydroxypentanoic acid gamma-lactone (2,4,5-TP) in their effects on
feeding behavior and humoral factors was assessed by infusion into the rat
third cerebroventricle. Initial transient food intake was most potently
affected by infusion of 2.50 mumol of the 2S,4S-stereoisomer of 2,4,5-TP
(80%) at 1100 h. Among the others, 2.50 mumol of the 2R,4S-isomer was
somewhat potent in feeding elicitation (20%). Feeding induced by these
isomers was not accompanied by periprandial drinking. Ambulation increased
with elicitation of feeding. During the first dark period after infusion at
1940 h, 2.50 mumol of the 3S-isomer of 3,4-DB decreased food intake,
including reduced meal size, and prolonged postprandial intermeal interval,
but the 3R-isomer did not. Potent hypoglycemia with hyperinsulinemia was
caused by the 2S,4S-isomer of 2,4,5-TP, and the S-isomer of 3,4-DB caused
responses that were reciprocal to those to 2,4,5-TP. The remaining isomers
did not affect feeding or humoral factors. The results suggest that the S-
or S,S-stereo-isomer of the endogenous organic acid gamma-lactones may be
important in modulating food intake through the hypothalamus.
