Antagonism of central growth hormone-releasing factor activity selectively attenuates dark-onset feeding in rats.
Exogenous growth hormone-releasing factor (GRF) has been shown to activate feeding by central mechanisms involving the suprachiasmatic nucleus/medial preoptic area (SCN/MPOA). Until now, however, the role played by endogenous GRF in the SCN/MPOA in naturally occurring eating has remained unknown. To investigate this, the effects of SCN/MPOA injections of GRF antiserum (AS-GRF) on feeding in rats were studied. In light of SCN involvement in the control of circadian rhythms, AS-GRF was tested during the light and dark phases of the photoperiod. Results indicated that AS-GRF significantly attenuated dark-onset feeding but had no effect on feeding during the mid-dark, mid-light, or light-onset periods. These results suggest that endogenous GRF does play a role in naturally occurring feeding and that it may be involved in the circadian organization of feeding.
Vaccarino
F J
FJ
Department of Psychology, University of Toronto, Ontario, Canada.
Feifel
D
D
Rivier
J
J
Vale
W
W
D000818:Animals; D001921:Brain / Q000378:metabolism*; D003624:Darkness; D005247:Feeding Behavior / Q000502:physiology*; D013007:Growth Hormone-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000276:immunology; D007106:Immune Sera / Q000276:immunology; D007267:Injections; D008297:Male; D011301:Preoptic Area / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D013493:Suprachiasmatic Nucleus / Q000502:physiology
D007106:Immune Sera; D013007:Growth Hormone-Releasing Hormone