Distribution of thyrotropin-releasing hormone receptor mRNA in rat peripheral tissues.

Since the thyrotropin-releasing hormone receptor (TRH-R) cDNA was isolated, the distribution of TRH-R mRNA has been investigated in the central nervous system (CNS) and the pituitary. However, there has been less genetical studies on the distribution of TRH-R mRNA in the peripheral tissues, although TRH exists not only in CNS but also in the peripheral tissues. In this study we investigated the distribution of TRH-R mRNA in rat peripheral tissues by reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis. TRH-R mRNA was detected in almost all of the peripheral tissues tested, although the amount varied considerably depending on the tissues. In the uterus, thymus, ovary, and testis, TRH-R mRNA levels appeared to be relatively high. These results suggest that TRH and its receptor have specific functions in the peripheral tissues as well as in CNS and in the pituitary.