Prolactin Receptor mRNA Expression in Fetal Rat Brain

Abstract

One of the target tissues for prolactin (PRL) family members is the central nervous sytem (CNS) in adult animals. In this study, we tried to detect PRL receptor (PRL-R) mRNAs in fetal rat brains. mRNAs extracted from various tissues, including the brain, on embryonic days 12 (E12), 14, 16, 18 and 20 were subjected to reverse transcriptional polymerase chain reaction (RT-PCR) using two sets of primers specific to the short and long forms of the PRL-R. The short form cDNA band (330 bp) was detected in the fetal brain from E12 to 20, whereas the long band (420 bp) was not apparently observed, suggesting that the developing fetal brain is a target for PRL family members. Short form PRL-R mRNA was also expressed in the liver (E20), heart (E12 to 20), intestine (E16 to 20) and forelimb (E20), and long form PRL-R was observed in the heart on E20. Semi-quantitative PCR analysis revealed that short form PRL-R mRNA expression in the fetal brain was as biphasic: constant on E12 and 14, and increased progressively on E18 and 20. Thus, PRL-R gene expression is initiated very early in developing fetal tissues, including the CNS.