Glycyl-L-glutamine antagonizes alpha-MSH-elicited thermogenesis.
The objective of this study was to determine whether glycyl-L-glutamine [beta-endorphin(30-31)] modulates the thermoregulatory actions of alpha-MSH. Microinjection of alpha-MSH (0.06 nmol) into PGE2-responsive thermogenic sites in the medial preoptic area of rats generated a hyperthermic response, inducing a 0.85 +/- 0.19 degrees C rise in colonic temperature (Tc) within 45 min. Coadministration of glycyl-L-glutamine (3.0 nmol) completely blocked the response, maintaining Tc at baseline levels. This was not attributable to glycyl-L-glutamine hydrolysis because coadministration of glycine and glutamine had no effect on alpha-MSH-induced thermogenesis. Glycyl-L-glutamine, injected alone, was similarly without effect. These data indicate that glycyl-L-glutamine inhibits alpha-MSH-induced thermogenesis but is devoid of thermoregulatory activity itself.
Resch
G E
GE
Division of Molecular Biology and Biochemistry, University of Missouri-Kansas City 64108.
Millington
W R
WR
D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects*; D015232:Dinoprostone / Q000494:pharmacology; D004151:Dipeptides / Q000008:administration & dosage*; D008297:Male; D009433:Neural Inhibition; D011301:Preoptic Area / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000521:alpha-MSH / Q000008:administration & dosage / Q000037:antagonists & inhibitors*
D004151:Dipeptides; C039788:glycylglutamine; D000521:alpha-MSH; D015232:Dinoprostone