Recently, testis has been known as a source of numerous hypothalamic neuropeptides, including thyrotrophin releasing hormone (TRH). We have found that TRH receptor (TRH R) mRNA was identified in leydig cells of mouse testis using in situ hybridization. In order to investigate the expression regulation of thyrotrophin releasing hormone (TRH) and TRH receptor (TRH R) in rat testis, and to study their function in reproduction and development, we designed oligonucleotide primers from the sequences of ra...