PLATELET-DERIVED GROWTH-FACTOR LIGAND AND RECEPTOR SUBUNIT MESSENGER-RNA IN THE SERTOLI AND LEYDIG-CELLS OF THE RAT TESTIS

The expression of mRNAs encoding the platelet-derived growth factor (P DGF) subunits (PDGF A and PDGF B) and the PDGF receptor subunits (PDGF -R alpha and PDGF-R beta) was studied in cells of the rat testis. Leyd ig cells, primary spermatocytes, round spermatids, and cytoplasts were isolated from adult animals, and enriched preparations of Sertoli cel ls were obtained from 20-day-old animals. RNA from these cells was exa mined using Northern blots. Messenger RNA encoding both the PDGF-R alp ha and PDGF-R beta subunits was observed in Leydig and Sertoli cell pr eparations but not in any of the germ cell samples. The Leydig cells c ontained predominantly mRNA encoding PDGF B subunits, while the Sertol i cells contained abundant mRNAs encoding both ligand subunits. Neithe r PDGF subunit mRNA was detected in the germ cells. This paper has not examined the expression of protein corresponding to the mRNAs detecte d but the data suggest that both paracrine and autocrine roles for PDG F are likely in the testis, and that PDGF may mediate communication be tween the interstitial compartment and the seminiferous epithelium.