Document Detail

Age-related decline in caloric intake and motivation for food in rhesus monkeys.
MedLine Citation:
PMID:  15748792     Owner:  NLM     Status:  MEDLINE    
Human studies have documented age-related declines in caloric intake that are pronounced at advanced ages. We examined caloric intake from a longitudinal study of aging in 60 male and 60 female rhesus monkeys (Macaca mulatta) collected for up to 10 years. Monkeys were provided a standardized, nutritionally fortified diet during two daily meals, and intake was measured quarterly. About half of the monkeys were on a regimen of caloric restriction (CR) representing about a 30% reduction in caloric intake compared to controls (CON) of comparable age and body weight. CR was applied to determine if this nutritional intervention retards the rate of aging in monkeys similar to observations in other mammalian studies. Following reproductive maturity at 6 years of age, there was a consistent age-related decline in caloric intake in these monkeys. Although males had higher intake than females, and CON had higher intake compared to CR, the sex and diet differences converged at older ages (>20 years); thus, older CR monkeys were no longer consuming 30% less than the CON. When adjusted for body weight, an age-related decline in caloric intake was still evident; however, females had higher intake compared to males while CR monkeys still consumed less food, and again differences converged at older ages. Motivation for food was assessed in 65 of the monkeys following at least 8 years in their respective diet groups. Using an apparatus attached to the home cage, following an overnight fast, monkeys were trained to reach out of their cage to retrieve a biscuit of their diet by pushing open a clear plastic door on the apparatus. The door was then locked, and thus the biscuit was irretrievable. The time spent trying to retrieve the biscuit was recorded as a measure of motivation for food. We observed an age-related decline in this measure, but found no consistent differences in retrieval time between CR and CON groups of comparable age and time on diet. The results demonstrate an age-related decline in food intake and motivation for food in rhesus monkeys paralleling findings in humans; however, we found no evidence that monkeys on a long-term CR regimen were more motivated for food compared to CON. Examining the relationship of selected blood proteins to food intake following 7-11 years on the study, we found a negative correlation between globulin and intake among males and females after accounting for differences in age. In addition, a positive correlation was observed between leptin and intake in males.
Julie A Mattison; Angela Black; Jennifer Huck; Tammy Moscrip; April Handy; Edward Tilmont; George S Roth; Mark A Lane; Donald K Ingram
Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2004-12-10
Journal Detail:
Title:  Neurobiology of aging     Volume:  26     ISSN:  0197-4580     ISO Abbreviation:  Neurobiol. Aging     Publication Date:  2005 Jul 
Date Detail:
Created Date:  2005-03-07     Completed Date:  2005-05-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8100437     Medline TA:  Neurobiol Aging     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1117-27     Citation Subset:  IM    
Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.
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MeSH Terms
Age Factors
Aging / physiology*
Albumins / metabolism
Behavior, Animal
Body Weight / physiology
Caloric Restriction / methods
Energy Intake / physiology*
Feeding Behavior / physiology*
Globulins / metabolism
Leptin / blood
Longitudinal Studies
Macaca mulatta
Reaction Time
Sex Factors
Reg. No./Substance:
0/Albumins; 0/Globulins; 0/Leptin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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