Quantitative reverse transcription and polymerase chain reaction analysis of oxytocin and vasopressin receptor mRNAs in the rat uterus near parturition.
Oxytocin receptors (OT-R) are known to be involved in the course of labor since a massive increase in OT-binding sites is observed in the uterus just before parturition. Vasopressin (AVP)-binding sites have also been observed and have been shown to mediate uterotonic responses. To determine exactly which subtypes of OT/AVP receptors are expressed in the rat uterus near parturition, we carried out absolute quantitations of the neurohypophysial hormone receptor (OT-R and the vasopressin receptors V1a-R, V1b-R and V2-R) mRNAs with an assay based on reverse transcription-polymerase chain reaction (RT-PCR) using in vitro transcribed mutated cRNAs as internal standards. The number of mRNA molecules/ng of total RNA was 35 +/- 6, 220 +/- 33 and 39 +/- 9 for OT-R (P < 0.01) and 16 +/- 1, 25 +/- 8 and 31 +/- 5 for V1a-R (P > 0.05) on day (D) 21, 22 and 23 of gestation (post-parturient), respectively. We did not detect V1b-R and V2-R mRNAs in the pregnant uterus. Therefore, the heterogeneity of OT and AVP receptors in the rat uterus can only be assigned to the presence of OT-R and V1a-R neurohypophysial hormone receptor subtypes, whereas V1b-R and V2-R can not be invoked. Only OT-R mRNA levels change in the uterus near parturition.
Clerget
M S
MS
Laboratoire de Neurobiologie des Fonctions Végétatives, INRA, Centre de Recherches de Jouy, Jouy en Josas, France.
Elalouf
J M
JM
Germain
G
G
D000818:Animals; D005260:Female; D007743:Labor, Obstetric / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy; D018075:RNA, Complementary / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018045:Receptors, Oxytocin / Q000235:genetics*; D017483:Receptors, Vasopressin / Q000235:genetics*; D014158:Transcription, Genetic; D014599:Uterus / Q000378:metabolism*
D018075:RNA, Complementary; D012333:RNA, Messenger; D018045:Receptors, Oxytocin; D017483:Receptors, Vasopressin