Estradiol decreases the orexigenic effect of neuropeptide Y, but not agouti-related protein, in ovariectomized rats

Jessica Santollo, Lisa A. Eckel

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


Available data suggest that estradiol exerts an inhibitory effect on food intake by modulating the actions of multiple gut- and brain-derived peptides implicated in the control of food intake. For example, recent studies have shown that estradiol decreases the orexigenic effects of ghrelin and melanin-concentrating hormone. In the present study, we examined estradiol's ability to decrease the actions of two additional orexigenic peptides, neuropeptide Y (NPY) and agouti-related protein (AgRP). Food intake was monitored following lateral ventricular infusions of 5 μg NPY, 10 μg AgRP, or saline vehicle in ovariectomized rats treated with either 1 μg estradiol or sesame oil vehicle. NPY increased food intake for 2 h in both oil- and estradiol-treated ovariectomized rats. During this interval, the orexigenic effect of NPY was significantly greater in oil-treated rats, relative to estradiol-treated rats. In contrast to the short-term action of NPY, a single injection of AgRP increased food intake for 3 days in oil- and estradiol-treated rats. Meal pattern analysis revealed that the orexigenic effect of AgRP is mediated by an increase in meal size, not meal number. Unlike that observed following NPY treatment, estradiol failed to modulate the magnitude by which AgRP increased food intake and meal size. We conclude that a physiological regimen of estradiol treatment decreases the orexigenic effect of NPY, but not AgRP, in ovariectomized rats.

Original languageEnglish
Pages (from-to)173-177
Number of pages5
JournalBehavioural Brain Research
Issue number2
StatePublished - Aug 22 2008

Bibliographical note

Funding Information:
This work was supported by a grant from the NIH (DK-073936) and an NIH Joint Neuroscience Predoctoral Training Grant (NIH, NIDCR, NIGMS, NIMH, NINDS, NINR).


  • AgRP
  • Estrous cycle
  • Food intake
  • Meal size
  • NPY

ASJC Scopus subject areas

  • Behavioral Neuroscience


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