Effect of ovarian steroid hormones and the presence of the fetus on oxytocin gene expression in the uterus

in Journal of Endocrinology
Authors:
T Higuchi
Search for other papers by T Higuchi in
Current site
Google Scholar
PubMed
Close
,
C-X Liu
Search for other papers by C-X Liu in
Current site
Google Scholar
PubMed
Close
,
H Saito
Search for other papers by H Saito in
Current site
Google Scholar
PubMed
Close
,
H Negoro
Search for other papers by H Negoro in
Current site
Google Scholar
PubMed
Close
, and
S Matsukawa
Search for other papers by S Matsukawa in
Current site
Google Scholar
PubMed
Close
Restricted access
Rent on DeepDyve

Sign up for journal news

Abstract

Oxytocin (OT) is a neurohypophysial hormone with potent stimulating activity of the pregnant uterus, but its physiological role in parturition is still unclear. Recently, OT was found to be synthesized in the pregnant uterus, indicating that OT originating from the uterus, not from the posterior pituitary gland, may trigger the onset of labour. In order to define the factors responsible for the induction of uterine OT, the effect of ovarian steroid hormones and conceptus on the induction of OT mRNA in the rat uterus was examined by Northern and dot blot hybridization analysis. OT mRNA in the uterus started to increase on day 14 of pregnancy and showed very high levels at the time of parturition. Uterine OT mRNA was not altered by any steroid treatment, oestradiol-17β (0·2 μg), progesterone (4 mg) or both in combination, for 6 days. The gravid horn of the uterus had 3·6-fold as much OT mRNA as the non-gravid horn on day 21 of pregnancy in hemipregnant rats with one ligated oviduct. The ovarian steroid hormones could not induce accumulation of OT mRNA in the uterus of ovariectomized rats, at least under the conditions used, but the presence of a conceptus may be critical for the very high levels of OT mRNA.

Journal of Endocrinology (1995) 146, 81–85

 

  • Collapse
  • Expand