Expression of mRNAs for transforming growth factor-beta receptors in the rat testis

In this study, we examined by means of northern blots, the mRNA expression of the three transforming growth factor-beta receptors (TGF-beta receptors) during rat testicular development and their cellular localization using fractionated testicular cells. Transcripts for receptors I and II were essentially detected in the immature testis, whereas receptor III mRNAs were present throughout testicular development. Somatic cells contained mRNAs for the three receptor types. In germ cells, transcripts for types I and II were in low abundance compared to type III mRNAs. In addition germ cells expressed three transcripts for the type III. Among the three transcripts, two were expressed exclusively in germ cells. TGF-beta being produced locally, our results are consistent with TGF-beta acting in testis via autocrine and/or paracrine mechanisms.