Peripheral insulin administration attenuates the increase in neuropeptide Y concentrations in the hypothalamic arcuate nucleus of fasted rats
Malabu, Usman H., McCarthy, H. David, McKibbin, Pauline E., and Williams, Gareth (1992) Peripheral insulin administration attenuates the increase in neuropeptide Y concentrations in the hypothalamic arcuate nucleus of fasted rats. Peptides, 13 (6). pp. 1097-1102.
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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.
|Item Type:||Article (Refereed Research - C1)|
|Keywords:||neuropeptide Y, fasting, hypothalamus, insulin, rat|
|Date Deposited:||08 Oct 2012 06:27|
|FoR Codes:||11 MEDICAL AND HEALTH SCIENCES > 1103 Clinical Sciences > 110306 Endocrinology @ 100%|
|SEO Codes:||92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920104 Diabetes @ 100%|