Document Detail

Opioid control of growth hormone in the suckled sow is primarily mediated through growth hormone releasing factor.
MedLine Citation:
PMID:  2114957     Owner:  NLM     Status:  MEDLINE    
Endogenous opioid peptides mediate the effect of suckling on LH and PRL in the domestic pig. However, the role of opioids in modulating GH during lactation in swine is not known. Primiparous sows that had been immunized against GRF(1-29) conjugated to human serum albumin (GRF-HSA, n = 5) or HSA (n = 4) were used to determine changes in GH after naloxone. Treatments were imposed in all sows on day 21 of lactation when antibody titers were 9100 +/- 1629. All sows received (i.v.) naloxone (0.25 mg/kg) or saline (0.0125 ml/kg) at 15 min intervals for 165 min. Active immunization against GRF-HSA during lactation decreased (P less than 0.05) mean concentration (4.8 +/- 0.2 vs 2.6 +/- 0.1 ng/ml) and frequency (1.5 +/- 0.3 vs 0.4 +/- 0.2 peaks/4 hr). Concentrations of LH and PRL were similar in GRF-HSA and HSA immunized sows. Naloxone suppressed (P less than 0.05) GH in all sows. In HSA sows, naloxone abolished episodic release of GH and decreased average, but not basal, concentrations of GH. In sows immunized against GRF-HSA, naloxone decreased (P less than 0.05) average and basal GH but failed to decrease frequency of GH release. Naloxone failed to alter frequency of LH release. Concentrations of PRL decreased (P less than 0.05) after naloxone in all sows. In conclusion, immunization against GRF-HSA blocked most of the effect of lactation on GH. Blocking opioid receptors with naloxone decreased GH and PRL in all sows. In contrast to previous findings naloxone had no effect on LH. Opioids alter concentrations of GH through a GRF dependent and GRF independent pathway.
J D Armstrong; K L Esbenshade; M T Coffey; E Heimer; R Campbell; T Mowles; A Felix
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Domestic animal endocrinology     Volume:  7     ISSN:  0739-7240     ISO Abbreviation:  Domest. Anim. Endocrinol.     Publication Date:  1990 Apr 
Date Detail:
Created Date:  1990-08-21     Completed Date:  1990-08-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8505191     Medline TA:  Domest Anim Endocrinol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  191-8     Citation Subset:  IM    
Department of Animal Science, North Carolina State University, Raleigh 27695-7621.
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MeSH Terms
Endorphins / physiology*
Growth Hormone / secretion*
Growth Hormone-Releasing Hormone / immunology,  physiology*
Hypothalamus / drug effects,  secretion
Lactation / metabolism*
Naloxone / pharmacology
Pituitary Gland / drug effects,  secretion
Swine / metabolism*
Reg. No./Substance:
0/Endorphins; 465-65-6/Naloxone; 9002-72-6/Growth Hormone; 9034-39-3/Growth Hormone-Releasing Hormone

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

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