Estrogen reduces cholecystokinin-induced c-Fos expression in the rat brain.
Recent reports have shown that estradiol increases the hypophagic effect of exogenous cholecystokinin-octapeptide (CCK). CCK is known to increase the expression of Fos, a marker of neuronal activation, in specific medullary and hypothalamic nuclei. The present experiment tested the hypothesis that as estradiol enhances that behavioral effects of CCK, there is a parallel amplification of CCK-induced Fos expression. Instead, estradiol pretreatment reduced the level of CCK-induced Fos expression in the nucleus of the solitary tract (NTS) and in the medial parvocellular region of the hypothalamic paraventricular nucleus (PVN). The number of Fos-containing cells in the supraoptic nucleus and other regions of the PVN were not affected by estradiol pretreatment. The results are consistent with the hypothesis that the NTS and/or the PVN may mediate the estrogen-induced increased sensitivity to peripheral inhibitory signals in the control of food intake.
Flanagan-Cato
L M
LM
Department of Psychology, University of Pennsylvania, Philadelphia 19104-6196, USA.
King
J F
JF
Blechman
J G
JG
O'Brien
M P
MP
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002766:Cholecystokinin / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D016762:Genes, fos / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004958:Estradiol; D002766:Cholecystokinin