Response to delivery stress is not mediated by beta-endorphin (1-31).
OBJECTIVE
The aim of the study was to determine the reaction of the melanotroph and corticotroph-type pituitary proopiomelanocortin (POMC) response to vaginal delivery and caesarean section stress. Furthermore, the relationship between the release of pituitary POMC fragments, gonadotropins and sexual steroids were examined.


METHODS
Blood samples were obtained from 10 women in labour on arrival in the birth room (t(A)), at cervix dilatation of 5 cm (t(B)) and immediately after spontaneous delivery (t(C)) and in 16 patients undergoing elective caesarean section before induction of anaesthesia (t(B)) and immediately after delivery (t(C)). Samples were analysed for cortisol, ACTH, authentic beta-endorphin, beta-endorphin immunoreactive material (IRM), acetyl-N-beta-endorphin IRM (NAC), beta-lipotropin (beta-LPH) IRM, oestradiol (E(2)), progesterone (P), prolactin (PRL), FSH and LH.


RESULTS
NAC representing the melanotroph-type pituitary POMC system did not increase during the course of caesarean section or spontaneous labour. In contrast, a significant increase of beta-endorphin IRM, beta-LPH IRM and ACTH were observed, representing an activation of the corticotroph-type POMC system. Highly significant correlations between POMC fragment concentrations during caesarean section and spontaneous labour were also observed. Sexual steroids (E(2) and P) decreased significantly. Except for beta-endorphin IRM and E(2) in course of spontaneous delivery no significant correlation was observed between POMC fragment and gonadotropins or sexual steroids.


CONCLUSIONS
Caesarean section and spontaneous delivery activated the corticotroph but not the melanotroph POMC system.
Harbach
Heinz
H
University of Giessen, Department of Anaesthesiology, Intensive Care, Pain Therapy, Rudolf-Buchheim-Str. 7, D-35385 Giessen, Germany. heinz.harbach@chiru.med.uni-giessen.de
Antrecht
Kerstin
K
Boedeker
Rolf-Hasso
RH
Hempelmann
Gunter
G
Markart
Philipp
P
Matejec
Reginald
R
Muehling
Joerg
J
Welters
Ingeborg
I
Zygmunt
Marek
M
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D002585:Cesarean Section; D036861:Delivery, Obstetric; D005260:Female; D042341:Gonadal Hormones / Q000097:blood; D006065:Gonadotropins, Pituitary / Q000097:blood; D006801:Humans; D011247:Pregnancy; D011333:Pro-Opiomelanocortin / Q000097:blood*; D013312:Stress, Physiological / Q000097:blood*; D001615:beta-Endorphin / Q000097:blood / Q000502:physiology*
D042341:Gonadal Hormones; D006065:Gonadotropins, Pituitary; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone