Document Detail

Abnormal response of the neuropeptide Y-deficient mouse reproductive axis to food deprivation but not lactation.
MedLine Citation:
PMID:  12697683     Owner:  NLM     Status:  MEDLINE    
Neuropeptide Y (NPY) plays a key role in both food intake and GnRH secretion. Food deprivation elevates hypothalamic NPY activity and suppresses LH and gonadal steroid secretion. Similarly, lactation up-regulates NPY expression as food consumption increases and estrous cycles cease. These observations suggest that NPY coordinates reproductive suppression in response to energy deficiency; if so, the reproductive axis of NPY knockout (KO) mice should be impervious to lactation and food deprivation. We monitored food consumption, body weight, and estrous cyclicity during lactation in NPY KO mice with large and small litters. NPY KO mice with either litter size resembled wild types (WTs) in weight regulation and food consumption. Large-litter mothers had longer anestrous periods and smaller pups at weaning, but NPY KOs and WTs did not differ in either respect. We also examined the LH response of NPY KO mice to 48 h without food. Basal levels of LH in ovariectomized NPY KO animals decreased in response to fasting, but LH levels in intact and estrogen-treated ovariectomized NPY KO animals did not. In contrast, WTs consistently showed fasting-induced suppression of LH. Our findings suggest that other systems can sustain the hyperphagia of lactation and NPY alone is not responsible for suppressing cyclicity during lactation. Nevertheless, the suppression of basal LH release that accompanies food deprivation in normal female mice appears to require the steroid-dependent actions of NPY.
Jennifer W Hill; Jon E Levine
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Endocrinology     Volume:  144     ISSN:  0013-7227     ISO Abbreviation:  Endocrinology     Publication Date:  2003 May 
Date Detail:
Created Date:  2003-04-16     Completed Date:  2003-05-22     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1780-6     Citation Subset:  AIM; IM    
Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, USA.
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MeSH Terms
Anestrus / physiology
Body Weight / physiology
Eating / physiology
Estradiol / pharmacology
Fasting / physiology
Food Deprivation / physiology*
Genitalia, Female / physiopathology*
Lactation / physiology*
Luteinizing Hormone / blood
Mice, Inbred Strains
Mice, Knockout
Neuropeptide Y / deficiency*
Grant Support
Reg. No./Substance:
0/Neuropeptide Y; 50-28-2/Estradiol; 9002-67-9/Luteinizing Hormone

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

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