Document Detail

Effects of periconceptional undernutrition on the initiation of parturition in sheep.
MedLine Citation:
PMID:  15331382     Owner:  NLM     Status:  MEDLINE    
In sheep, parturition is initiated by increased fetal hypothalamic-pituitary-adrenal axis (HPAA) activity leading to PGE(2) and PGF(2alpha) production and a rise in the 17beta-estradiol-progesterone (E(2)/P(4)) ratio. Uteroplacental PG production can also increase fetal HPAA activity. Periconceptional maternal undernutrition accelerates fetal HPAA maturation resulting in preterm labor. We determined whether preterm labor was preceded by an increase in PG concentrations and E(2)/P(4) ratio and whether these increases preceded or followed the corresponding rise in cortisol concentrations. Singleton-bearing ewes were nourished ad libitum (N, n = 9) or undernourished (UN, n = 10) to reduce maternal weight by 15% from -61 days (d) to +30 d after mating with ad libitum intake thereafter. Paired maternal and fetal blood samples were collected from 126 d until delivery. Half the UN group delivered prematurely (>2 SD below mean gestation for the flock). PG and cortisol concentrations and E(2)/P(4) ratio increased before delivery in the same way in both groups. However, the increases occurred 7-10 d earlier in UN than in N animals. In both UN and N fetuses cortisol concentrations rose before fetal and maternal PG concentrations and maternal E(2)/P(4) ratio. Periconceptional maternal undernutrition induces preterm delivery in sheep by advancing the expected prepartum rise in cortisol and PG concentrations and E(2)/P(4) ratio. The rise in fetal cortisol concentration precedes the rise in fetal and maternal PG concentrations and maternal E(2)/P(4) ratio, suggesting that the underlying mechanism is likely to be acceleration of fetal HPAA maturation, resulting in initiation of the normal process of parturition.
Vasumathy Kumarasamy; Murray D Mitchell; Frank H Bloomfield; Mark H Oliver; Melanie E Campbell; John R G Challis; Jane E Harding
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-08-26
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  288     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2005 Jan 
Date Detail:
Created Date:  2004-12-13     Completed Date:  2005-03-02     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R67-72     Citation Subset:  IM    
Liggins Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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MeSH Terms
Animals, Newborn / blood
Dinoprost / analogs & derivatives*,  blood
Dinoprostone / blood
Estradiol / blood
Fetal Blood / metabolism
Food Deprivation
Gestational Age
Parturition / physiology*
Premature Birth / physiopathology
Prenatal Nutritional Physiological Phenomena / physiology*
Progesterone / blood
Reg. No./Substance:
27376-76-7/15-keto-13,14-dihydroprostaglandin F2alpha; 363-24-6/Dinoprostone; 50-28-2/Estradiol; 551-11-1/Dinoprost; 57-83-0/Progesterone

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

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