Document Detail


Activation of the hypothalamo-pituitary-adrenal axis by isolation and restraint stress during lactation in ewes: effect of the presence of the lamb and suckling.
MedLine Citation:
PMID:  16574791     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We investigated the effect of the presence and absence of lambs and suckling by lambs to attenuate activation of the hypothalamo-pituitary-adrenal (HPA) axis to isolation and restraint stress in lactating sheep. In experiment 1, blood samples were collected every 10 min from nonlactating (n = 5) and lactating (n = 5) ewes for 4 h before and during stress. In experiment 2, ewes (n = 6) were allocated to 1) nonlactating, 2) lactating with lambs absent, 3) lactating with lambs present but unable to suckle, and 4) lactating with lambs present and able to suckle. Blood samples were collected over 8 h with no stress (control day) and for 4 h before and 4 h during stress (stress day). In experiment 1, the mean (+/-SEM) cortisol concentrations increased significantly (P < 0.05) in nonlactating ewes during stress but did not change in lactating ewes. In experiment 2, cortisol did not vary on the control day or pretreatment of the stress day but increased (P < 0.05) during stress in all groups except lactating ewes with lambs present and able to suckle. The greatest cortisol response occurred in nonlactating ewes followed by lactating ewes with lambs absent and lactating ewes with lambs present but unable to suckle. During stress, the ACTH concentrations increased (P < 0.05) in nonlactating ewes and lactating ewes with lambs absent but not in lactating ewes with lambs present. We conclude that the activity of the HPA axis during isolation and restraint is reduced in lactating ewes and that the presence of lambs increases this level of attenuation.
Authors:
A J Tilbrook; A I Turner; M D Ibbott; I J Clarke
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-03-30
Journal Detail:
Title:  Endocrinology     Volume:  147     ISSN:  0013-7227     ISO Abbreviation:  Endocrinology     Publication Date:  2006 Jul 
Date Detail:
Created Date:  2006-06-16     Completed Date:  2006-07-24     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3501-9     Citation Subset:  AIM; IM    
Affiliation:
Department of Physiology, P.O. Box 13 F, Monash University, Clayton 3800, Australia. alan.tilbrook@med.monash.edu.au
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MeSH Terms
Descriptor/Qualifier:
Adrenocorticotropic Hormone / blood
Animals
Female
Hydrocortisone / blood
Hypothalamus / physiology*
Lactation*
Pituitary-Adrenal System / physiology*
Radioimmunoassay
Sheep
Stress, Psychological
Time Factors
Chemical
Reg. No./Substance:
50-23-7/Hydrocortisone; 9002-60-2/Adrenocorticotropic Hormone

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


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