Age-related alterations in the long-term regulation of food intake and body weight
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1
University of Pécs, Department of Pathophysiology and Gerontology, Medical School, Hungary
Long-term regulation of energy balance is characterized by two major tendencies: weight gain of the middle-aged and later anorexia and consequent loss of active tissues, leading to sarcopenia of the old population. In the background of these alterations, complex age-related shifts in the activity of the hypothalamic catabolic and anabolic neurohumoral systems may be assumed. Anabolic substances increase body weight (BW) via enhancement of food intake (FI) and suppression of metabolic rate, while catabolic mediators act in an opposite way.
Our aim was to study the central effects of catabolic alpha-melanocyte-stimulating hormone (α-MSH), catabolic corticotropin releasing factor (CRF), and of anabolic neuropeptide Y (NPY) on FI in different age-groups of rats.
Male Wistar rats aged 6-weeks, 3-4-, 6-, 12-, 18- or 24-months represented the human juvenile, young adult, 2 middle-aged and 2 old groups, respectively. FI-values were measured in an automated Feedscale system (Colombus) following intracerebroventricular injections of α-MSH (5 µg), CRF (0.3 µg), NPY (5 µg) or saline.
Alpha-MSH and CRF suppressed, NPY increased FI significantly. Administration of α-MSH considerably attenuated both spontaneous FI and re-feeding following 24-h fasting. The suppression of re-feeding varied between age groups: 22 % reduction was shown in juvenile, strong suppression (69 %) in young adult rats, which was attenuated by middle-age (56 % vs. 26 %), and was extreme (94 % vs. 74 %) in old animals. The catabolic effects of CRF were also weaker in middle-aged rats as compared to young ones. Anabolic NPY on the other hand showed an improved efficacy in the middle-aged and a decreased one in the old age group. Our experiments suggest characteristic age-related changes in the effects of central neuropeptides, which might contribute to the explanation of both the development of middle-aged obesity and sarcopenia in the old.
OTKA 49321, PTE ÁOK-KA-34039-25/2009, GVOP-3.2.1.-2004-0271/3.0.
Conference:
IBRO International Workshop 2010, Pécs, Hungary, 21 Jan - 23 Jan, 2010.
Presentation Type:
Poster Presentation
Topic:
Homeostatic and neuroendocrine systems
Citation:
Szabad
ÁO,
Schmidt
A,
Barcza
Z,
Balaskó
M and
Székely
M
(2010). Age-related alterations in the long-term regulation of food intake and body weight.
Front. Neurosci.
Conference Abstract:
IBRO International Workshop 2010.
doi: 10.3389/conf.fnins.2010.10.00132
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Received:
28 Apr 2010;
Published Online:
28 Apr 2010.
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Correspondence:
Árpád O Szabad, University of Pécs, Department of Pathophysiology and Gerontology, Medical School, Pécs, Hungary, mmbalasko@gmail.com