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Exp Gerontol. 2013 Nov;48(11):1180-8. doi: 10.1016/j.exger.2013.07.006. Epub 2013 Jul 19.

Age and nutritional state influence the effects of cholecystokinin on energy balance.

Author information

1
Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary. Electronic address: marta.balasko@aok.pte.hu.

Abstract

Cholecystokinin (CCK) is anorexic, irrespective whether it is applied intraperitoneally (IP) or intracerebroventricularly (ICV) in male Wistar rats. The metabolic effects depend on the route of administration: by the IP route it elicits hypothermia (presumably by type-1 receptors, CCK1R-s), while ICV administration is followed by fever-like hypermetabolism and hyperthermia via activation of CCK2R-s, which latter response seems to be most important in the postprandial (compensatory) hypermetabolism. The efficacy of the IP injected CCK varies with age: it causes strong anorexia in young adult 4 and 6-months old and again in old rats (aged 18-24 months), but the middle-aged (12-month old) ones seem to be resistant to this effect. Such pattern of effects may contribute to the explanation of age-related obesity observed in middle-aged animals as well as to the aging anorexia and loss of body weight in old ones. Diet-induced obesity accelerates the appearance of CCK-resistance as well as the return of high sensitivity to CCK in further aging, while chronic calorie-restriction prevents the development of resistance, as if the speed of the age-related regulatory changes was altered by the nutritional state. The effects of ICV applied CCK also change with age: the characteristic anorexic and hypermetabolic/hyperthermic effects can be observed in young adult rats, but the effects gradually and monotonically decline with age and disappear by the old age of 24 months. These disparate age-related patterns of CCK efficacy upon peripheral or central administration routes may indicate that although both peripheral and central CCKR-s exert anorexic effects, they may have dissimilar roles in the regulation of overall energy balance.

KEYWORDS:

Aging; Calorie-restriction; Cholecystokinin; Food intake; Metabolic rate; Obesity

PMID:
23876629
DOI:
10.1016/j.exger.2013.07.006
[Indexed for MEDLINE]
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