AJP - Regulatory, Integrative and Comparative Physiology, Vol 259, Issue 3 651-R657, Copyright © 1990 by American Physiological Society
Characterization of feeding behavior induced by central injection of GRF
P. R. Dickson and F. J. Vaccarino
Department of Psychology, University of Toronto, Ontario, Canada.
The behavior resulting from injection of rat hypothalamic growth
hormone-releasing factor (GRF) (0, 0.01, 0.1, 1.0 pmol) into the
suprachiasmatic nucleus-medial preoptic area (SCN/MPOA) or the
paraventricular nucleus (PVN) of the hypothalamus was examined. After
injections of GRF, feeding and other behavioral responses of male Wistar
rats were observed for 90 min. In the SCN/MPOA, GRF dose dependently
increased food intake, increasing mean meal length at 0.1 pmol and
increasing rate of eating with no effect on meal length at 1.0 pmol. Other
behavioral measures were unaffected by GRF. There was no effect after
injections into the PVN. These data are taken as confirmation that the
SCN/MPOA region of the hypothalamus is important for the central
stimulatory effects of GRF on feeding. The possibility that the PVN is
involved in the expression of feeding derived from intra-SCN/MPOA GRF
injections is discussed.
