Increased neuropeptide Y concentrations in specific hypothalamic regions of lactating rats: possible relationship ot hyperphagia and adaptive changes in energy balance

Malabu, Usman H., Kilpatrick, Anne, Ware, Mark, Vernon, Richard G., and Williams, Gareth (1994) Increased neuropeptide Y concentrations in specific hypothalamic regions of lactating rats: possible relationship ot hyperphagia and adaptive changes in energy balance. Peptides, 15 (1). pp. 83-97.

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Abstract

Lactation is accompanied by hyperphagia and a reduction in brown adipose tissue (BAT) thermogenesis, which are unexplained. Neuropeptide Y (NPY) powerfully stimulates feeding and inhibits BAT thermogenesis when injected into the paraventricular nucleus and other specific regions of the rat hypothalamus. We have tested the hypothesis that hypothalamic NPY activity is increased in lactating rats. Lactating rats consumed over four times as much food as nonlactating controls (n = 10; p < 0.001). Final plasma insulin concentrations in lactating rats were lower than in controls (6.8 ± 0.8 vs. 11.7 ± 2.1 pmol/1; p < 0.05) although plasma glucose and corticosterone concentrations were comparable (p > 0.05). Lactating rats showed significantly higher NPY levels than controls in specific hypothalamic regions, namely the arcuate nucleus-median eminence complex (a 41% rise; p < 0.001), paraventricular nucleus (35%; p < 0.001), ventromedial nucleus (66%; p = 0.003), and dorsomedial nucleus (78%; p < 0.001). Other hypothalamic regions showed no significant differences between groups. Increased NPY concentrations in specific hypothalamic regions, particularly the arcuate nucleus where NPY is synthesized, suggest increased activity of the hypothalamic NPYergic system in lactation. Neuropeptide Y may mediate hyperphagia and reduced BAT thermogenesis in lactation. Hypoinsulinemia may be a stimulus to hypothalamic NPY in lactation, as has been postulated in other conditions of negative energy balance.

Item ID: 23496
Item Type: Article (Refereed Research - C1)
Keywords: neuropeptide Y, lactation, hyperphagia, hypothalamus, rat
ISSN: 1873-5169
Date Deposited: 08 Oct 2012 06:36
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%
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