Document Detail

Plasma leptin-binding activity and hypothalamic leptin receptor expression during pregnancy and lactation in the rat.
MedLine Citation:
PMID:  12021059     Owner:  NLM     Status:  MEDLINE    
Leptin, the 16-kDa peptide hormone product of the ob gene, regulates body weight via the hypothalamus but also influences several aspects of reproductive function. Results of previous studies have suggested that pregnancy is a state of leptin resistance, because food consumption remains stable or increases despite a progressive rise in plasma leptin across most of gestation. In the present study, we assessed whether this apparent leptin resistance during rat pregnancy was due to either increased plasma leptin-binding activity and/or reduced expression of hypothalamic leptin receptor. Plasma leptin increased from 2.2 +/- 0.4 ng/ml before pregnancy to a maximum at midgestation (4.2 +/- 0.8 ng/ml on Day 12) and then fell by Day 22 and remained low throughout lactation. Despite the higher plasma leptin levels in pregnancy, food consumption increased from a minimum of 13.6 +/- 0.5 g/day before pregnancy to a peak of 21.9 +/- 0.6 g/day on Day 19, then fell before parturition (11.9 +/- 0.4 g/day on Day 22). At least part of the increase in plasma leptin during pregnancy was attributable to a marked increase (P < 0.001) in plasma leptin-binding activity between diestrus and late pregnancy, which then fell after birth but remained at midpregnancy levels to at least Day 12 of lactation. Hypothalamic expression of mRNA encoding the long form of the leptin receptor (Ob-Rb) was elevated in early pregnancy (Day 7) but returned to prepregnancy levels by midgestation and remained stable thereafter. The results of this study confirm that pregnancy in the rat is a state of relative leptin resistance, which is due primarily to increased plasma leptin-binding activity rather than to changes in hypothalamic Ob-Rb expression.
Ruth M Seeber; Jeremy T Smith; Brendan J Waddell
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biology of reproduction     Volume:  66     ISSN:  0006-3363     ISO Abbreviation:  Biol. Reprod.     Publication Date:  2002 Jun 
Date Detail:
Created Date:  2002-05-21     Completed Date:  2003-01-14     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0207224     Medline TA:  Biol Reprod     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1762-7     Citation Subset:  IM    
School of Anatomy and Human Biology and The Western Australian Institute for Medical Research, University of Western Australia, Crawley, Perth, Western Australia 6009, Australia.
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MeSH Terms
Blood Proteins / metabolism
Drug Resistance
Gene Expression*
Gestational Age
Hypothalamus / metabolism*
Leptin / blood*
Pregnancy, Animal / physiology*
Protein Binding
RNA, Messenger / analysis
Rats, Wistar
Receptors, Cell Surface / genetics*
Receptors, Leptin
Reference Values
Reg. No./Substance:
0/Blood Proteins; 0/Leptin; 0/RNA, Messenger; 0/Receptors, Cell Surface; 0/Receptors, Leptin

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