Maternal plasma corticotropin-releasing factor (CRF) and CRF-binding protein (CRF-BP) levels in post-term pregnancy: effect of prostaglandin administration.
OBJECTIVE
Placental corticotropin-releasing factor (CRF) affects myometrial contractility and the secretion of several uterotonins such as prostaglandins (PGs); however, the activity of CRF is counteracted by CRF-binding protein (CRF-BP). At term and pre-term labor, CRF levels in maternal plasma are highest whereas those of CRF-BP are falling, and the cause of this fall is unknown. Thus, in this study, we investigated the effect of PG administration for labor induction on maternal plasma CRF and CRF-BP concentrations.


METHODS
Maternal plasma CRF and CRF-BP levels were assayed before and after (2 h later) induction of labor by intracervical administration of prostaglandin E(2) (PGE(2)), and at delivery in a group of healthy post-term pregnancies (n=18). Controls were women at term out of labor (n=22), who subsequently progressed to deliver a healthy singleton baby.


METHODS
CRF was measured by two-site immunoradiometric assay, and CRF-BP was assayed by radioimmunoassay.


RESULTS
Maternal plasma CRF levels were significantly (P<0.0001) lower and CRF-BP significantly (P<0.0005) higher in post-term than in term pregnancies. With respect to induction of labor, 2 mg PGE(2) were sufficient to increase maternal plasma CRF levels at delivery (P<0.005). While 0.5 mg PGE(2) significantly decreased maternal plasma CRF-BP levels at delivery (P<0.001), 2.0 mg PGE(2) significantly reduced CRF-BP concentrations both after 2 h (P<0.05) and at delivery (P<0.0001).


CONCLUSIONS
In the light of the well-known stimulation of prostaglandin release by CRF, these data suggest a positive feedback effect of PGE(2) on maternal CRF release during induced labor.
Florio
P
P
Department of Pediatrics, Section of Obstetrics and Gynecology, Obstetrics and Reproductive Medicine, University of Siena, Policlinico Le Scotte Viale Bracci, 53100, Siena, Italy. florio@unisi.it
Lowry
P J
PJ
Benedetto
C
C
Galleri
L
L
Torricelli
M
M
Giovannelli
A
A
Battista
R
R
Reis
F M
FM
Petraglia
F
F
D000328:Adult; D002352:Carrier Proteins / Q000097:blood*; D003346:Corticotropin-Releasing Hormone / Q000097:blood*; D015232:Dinoprostone / Q000008:administration & dosage* / Q000378:metabolism; D025461:Feedback, Physiological / Q000187:drug effects; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007751:Labor, Induced / Q000379:methods*; D010120:Oxytocics / Q000008:administration & dosage* / Q000378:metabolism; D036801:Parturition / Q000097:blood / Q000187:drug effects; D011247:Pregnancy; D011273:Pregnancy, Prolonged / Q000097:blood*; D014590:Uterine Contraction / Q000187:drug effects / Q000378:metabolism
D002352:Carrier Proteins; D010120:Oxytocics; C067133:corticotropin releasing factor-binding protein; D003346:Corticotropin-Releasing Hormone; D015232:Dinoprostone