Estradiol treatment fails to affect the feeding responses to melanocortin-3/4 receptor agonism or antagonism in ovariectomized rats.
The involvement of the hypothalamic melanocortin-3 and -4 (MC3/4) receptors system in the inhibitory actions of estradiol (E2) on feeding was investigated. Ovariectomized Long-Evans rats with lateral ventricular (LICV) injection cannulae were maintained on a near-physiological, cyclic schedule of E2 treatment. LICV injections of 0.5 nmol of the MC3/4 agonist MTII decreased feeding, and LICV injections of the MC3/4 antagonists SHU9119 (12.5-500 pmol) and AgRP (1.0 nmol) stimulated feeding. None of these effects was affected by E2 treatment. Thus, hypothalamic MC3/4 receptors play a physiological role in the control of feeding in female rats as in males but do not mediate E2's feeding effects during the ovarian cycle.
Polidori
Carlo
C
Department of Psychiatry, Joan and Sanford I. Weill Medical College of Cornell University, New York, NY 10021, USA.
Geary
Nori
N
D054369:Agouti-Related Protein; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects*; D005260:Female; D007031:Hypothalamus / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology; D010053:Ovary / Q000502:physiology; D011506:Proteins / Q000378:metabolism; D051381:Rats; D044104:Receptor, Melanocortin, Type 3; D044105:Receptor, Melanocortin, Type 4; D018043:Receptors, Corticotropin / Q000037:antagonists & inhibitors / Q000378:metabolism; D012737:Sex Factors; D000521:alpha-MSH / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology
D054369:Agouti-Related Protein; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D044104:Receptor, Melanocortin, Type 3; D044105:Receptor, Melanocortin, Type 4; D018043:Receptors, Corticotropin; C081720:alpha-MSH (4-10)amide, Ac-Nle(4)-cyclo(Asp(5)-Phe(7)-Lys(10))-; C103272:SHU 9119; D004958:Estradiol; D000521:alpha-MSH; D009074:Melanocyte-Stimulating Hormones