Peripheral insulin administration attenuates the increase in neuropeptide Y concentrations in the hypothalamic arcuate nucleus of fasted rats

doi:10.1016/0196-9781(92)90013-S

Peptides

Volume 13, Issue 6, November–December 1992, Pages 1097-1102

https://doi.org/10.1016/0196-9781(92)90013-S Get rights and content

Abstract

Fasting increases neuropeptide Y (NPY) concentrations in the arcuate nucleus (ARC), its site of synthesis, and in other regions of the rat hypothalamus. Neuropeptide Y is a potent central orexigenic agent and may therefore stimulate appetite during fasting. We tested the hypothesis that low plasma insulin levels stimulate ARC levels of NPY in fasted rats. Compared with freely fed controls (n = 8), rats fasted for 72 h (n = 8) showed significantly lower plasma insulin levels (28.9 ± 1.6 vs. 52.6 ± 5.7 pmol/l; p < 0.001) and higher ARC NPY concentrations (14.2 ± 1.8 vs. 8.4 ± 2.2 fmol/μg protein; p < 0.001). Fasted rats treated with subcutaneous insulin (5 U/kg/day; n = 10), which nearly normalized plasma insulin (46.6 ± 2.8 pmol/l), showed intermediate ARC NPY levels (11.2 ± 1.4 fmol/μg protein; p < 0.01 vs. controls and untreated fasted rats). Insulin administered peripherally, therefore, attenuates fasting-induced NPY increases in the ARC, supporting the hypothesis that hypoinsulinemia stimulates hypothalamic NPY.

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Peripheral insulin administration attenuates the increase in neuropeptide Y concentrations in the hypothalamic arcuate nucleus of fasted rats

Abstract

Regul. Pept.

Physiol. Behav.

Brain Res.

Neurosci. Lett.

Neurosci. Lett.

Peptides

Peptides

Regul. Pept.

Life Sci.

Peptides

Peptides

Insulin in the brain

Annu. Rev. Physiol.

Intraventricular insulin reduces food intake and body weight of lean but not obese Zucker rats

Appetite

Neuropeptide Y secretion increases in the paraventricular nucleus in association with increased appetite for food

Divergent effects of insulin on IGF II gene expression in the rat hypothalamus

Endocrinology

Protein measurement with the Folin phenol reagent

J. Biol. Chem.

Altered neuropeptide Y concentrations in specific hypothalamic regions of obese (fa/fa) Zucker rats: Possible relationship to obesity and neuroendocrine disturbances

Diabetes