PMID- 11250660
OWN - NLM
STAT- MEDLINE
DCOM- 20010426
LR  - 20190709
IS  - 0022-0795 (Print)
IS  - 0022-0795 (Linking)
VI  - 169
IP  - 1
DP  - 2001 Apr
TI  - Endomorphins and activation of the hypothalamo-pituitary-adrenal axis.
PG  - 185-93
AB  - Endomorphin (EM)-1 and EM-2 are opioid tetrapeptides recently located in the 
      central nervous system and immune tissues with high selectivity and affinity for 
      the mu-opioid receptor. Intracerebroventricular (i.c.v.) administration of 
      morphine stimulates the hypothalamo-pituitary-adrenal (HPA) axis. The present 
      study investigated the effect of centrally administered EM-1 and EM-2 on HPA axis 
      activation. Rats received a single i.c.v. injection of either EM-1 (0.1, 1.0, 10 
      microg), EM-2 (10 microg), morphine (10 microg), or vehicle (0.9% saline). Blood 
      samples for plasma corticosterone determinations were taken immediately prior to 
      i.c.v. administration and at various time points up to 4 h post-injection. Trunk 
      blood, brains and pituitaries were collected at 4 h. Intracerebroventricular 
      morphine increased plasma corticosterone levels within 30 min, whereas EM-1 and 
      EM-2 were without effect. In addition, pre-treatment of i.c.v. EM-1 did not block 
      the rise in corticosterone after morphine. Corticotrophin-releasing factor (CRF) 
      mRNA and arginine vasopressin (AVP) mRNA in the paraventricular nucleus (PVN) and 
      POMC mRNA in the anterior pituitary were found to be unaffected by either 
      morphine or endomorphins. Since release of other opioids are elevated in response 
      to acute stress, we exposed rats to a range of stressors to determine whether 
      plasma EM-1 and EM-2 can be stimulated by HPA axis activation. Plasma 
      corticosterone, ACTH and beta-endorphin were elevated following acute restraint 
      stress, but concentrations of plasma EM-1-immunoreactivity (ir) and EM-2-ir did 
      not change significantly. Corticosterone, ACTH and beta-endorphin were further 
      elevated in adjuvant-induced arthritis (AA) rats by a single injection of 
      lipopolysaccharide (LPS), but not by restraint stress. In conclusion, neither 
      EM-1 or EM-2 appear to influence the regulation of the HPA axis. These data 
      suggest that endomorphins may be acting on a different subset of the mu-opioid 
      receptor than morphine. The failure to induce changes in plasma EM-ir in response 
      to the chronic inflammatory stress of AA, the acute immunological stress of LPS, 
      or the psychological stress of restraint, argues against an important role for 
      endomorphins in mediating HPA axis activity.
FAU - Coventry, T L
AU  - Coventry TL
AD  - University Research Centre for Neuroendocrinology, University of Bristol, Bristol 
      Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK.
FAU - Jessop, D S
AU  - Jessop DS
FAU - Finn, D P
AU  - Finn DP
FAU - Crabb, M D
AU  - Crabb MD
FAU - Kinoshita, H
AU  - Kinoshita H
FAU - Harbuz, M S
AU  - Harbuz MS
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - J Endocrinol
JT  - The Journal of endocrinology
JID - 0375363
RN  - 0 (Lipopolysaccharides)
RN  - 0 (Oligopeptides)
RN  - 0 (Receptors, Opioid, mu)
RN  - 0 (endomorphin 1)
RN  - 3PH5M0466G (endomorphin 2)
RN  - 60617-12-1 (beta-Endorphin)
RN  - 76I7G6D29C (Morphine)
RN  - 9002-60-2 (Adrenocorticotropic Hormone)
RN  - W980KJ009P (Corticosterone)
SB  - IM
MH  - Adrenocorticotropic Hormone/blood
MH  - Analysis of Variance
MH  - Animals
MH  - Arthritis, Reactive/blood
MH  - Chromatography, High Pressure Liquid
MH  - Corticosterone/blood
MH  - Hypothalamo-Hypophyseal System/*drug effects/metabolism
MH  - In Situ Hybridization/methods
MH  - Lipopolysaccharides/pharmacology
MH  - Male
MH  - Morphine
MH  - Oligopeptides/blood/*pharmacology
MH  - Pituitary-Adrenal System/*drug effects/metabolism
MH  - Radioimmunoassay/methods
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Receptors, Opioid, mu/*agonists
MH  - Stimulation, Chemical
MH  - Stress, Psychological
MH  - beta-Endorphin/blood
EDAT- 2001/03/16 10:00
MHDA- 2001/05/01 10:01
CRDT- 2001/03/16 10:00
PHST- 2001/03/16 10:00 [pubmed]
PHST- 2001/05/01 10:01 [medline]
PHST- 2001/03/16 10:00 [entrez]
AID - JOE03894 [pii]
AID - 10.1677/joe.0.1690185 [doi]
PST - ppublish
SO  - J Endocrinol. 2001 Apr;169(1):185-93. doi: 10.1677/joe.0.1690185.