Document Detail


Reduced food intake in zinc deficient rats is normalized by megestrol acetate but not by insulin-like growth factor-I.
MedLine Citation:
PMID:  9430615     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Zinc deficiency in rats results in impaired growth accompanied by decreased and cyclic food intake. These signs are associated with decreased plasma insulin-like growth factor-I (IGF-I), a major mediator of growth. The purpose of this study was to determine the relationship between decreased plasma IGF-I and the impairment of appetite and growth in zinc deficiency. Immature male rats were fed free choice a low zinc (<1 mg/kg) diet (-Zn) or a zinc adequate (100 mg/kg) control diet (+Zn). Plasma IGF-I concentrations were normalized in zinc-deficient rats by the following two methods: osmotic pump infusion of IGF-I (2.4 mg/kg body weight daily) and oral administration (50 mg/kg body weight twice daily) of the synthetic progestin, megestrol acetate (MA). Infusion of IGF-I for 8 d sustained plasma IGF-I concentrations in zinc-deficient rats at control levels but had no effect on either food intake or growth rate. MA administration for 8 d maintained the plasma IGF-I of deficient rats and significantly increased food intake. The early aspects of cyclic food intake were eliminated, and, after a few days, food intake of deficient rats given MA was not different than that of controls. MA increased food intake and fat deposition regardless of zinc status, but it had no effect on the growth rate of deficient rats. MA significantly decreased body weight of controls, uncoupling energy intake and gain. The results suggest that reduced food intake precedes the decreased plasma IGF-I concentration and that IGF-I is not responsible for the decreased growth and food intake of zinc-deficient rats. The appetite and growth impairment of zinc-deficient rats may arise from disrupted function of IGF-I receptors in the brain and peripheral tissues, but not from low circulating levels of IGF-I.
Authors:
J D Browning; R S MacDonald; W H Thornton; B L O'Dell
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  The Journal of nutrition     Volume:  128     ISSN:  0022-3166     ISO Abbreviation:  J. Nutr.     Publication Date:  1998 Jan 
Date Detail:
Created Date:  1998-01-29     Completed Date:  1998-01-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0404243     Medline TA:  J Nutr     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  136-42     Citation Subset:  IM    
Affiliation:
Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.
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MeSH Terms
Descriptor/Qualifier:
Adipose Tissue
Animals
Appetite Stimulants / pharmacology*
Body Composition
Diet
Eating / drug effects*
Insulin-Like Growth Factor I / metabolism,  pharmacology*
Male
Megestrol Acetate / pharmacology*
Rats
Rats, Wistar
Weight Gain / drug effects
Zinc / administration & dosage,  deficiency*
Chemical
Reg. No./Substance:
0/Appetite Stimulants; 51154-23-5/Megestrol Acetate; 67763-96-6/Insulin-Like Growth Factor I; 7440-66-6/Zinc

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


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