Identification of a non-mitogenic paracrine factor involved in mesenchymal-epithelial cell interactions between testicular peritubular cells and Sertoli cells.
Seminiferous peritubular cells have previously been shown to secrete a protein termed P-Mod-S which modulates the functions of Sertoli cells. The present study provides an initial characterization of P-Mod-S and examines the actions of P-Mod-S on Sertoli cells. Gel filtration chromatography demonstrates that P-Mod-S has an apparent molecular weight of 70 000 that could not be dissociated to a lower molecular weight form. A 40- to 90-fold purification of P-Mod-S was obtained with a predicted half maximal effective concentration for Sertoli cells of less than 10(-9) M. Through an analysis of the actions of P-Mod-S on Sertoli cells it is demonstrated that P-Mod-S stimulates the Sertoli cell to a greater extent than any single hormone or vitamin known to influence the cell. P-Mod-S maximally stimulates testicular transferrin and androgen-binding protein production by Sertoli cells, but does not stimulate levels of plasminogen activator activity. P-Mod-S also appears to induce the synthesis of several proteins that are not detected in control non-treated Sertoli cell cultures. One such protein whose synthesis was stimulated by P-Mod-S treatment of Sertoli cells was a component having a molecular mass of 20 kDa. This 20 kDa Sertoli cell-secreted protein was specifically immunoprecipitated with an antibody against an epididymal lactalbumin-like protein. This implies that P-Mod-S can induce Sertoli cells to synthesize and secrete a lactalbumin-like protein. P-Mod-S was found not to contain mitogenic activity. Data presented indicate that testicular peritubular cells synthesize and secrete a 70 kDa non mitogenic paracrine factor termed P-Mod-S which has a dramatic influence on Sertoli cell functions. Results are discussed with respect to modulation of epithelial (Sertoli) cell functions by components produced by mesenchymal (peritubular) cells.
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D000727:Androgen-Binding Protein / Q000096:biosynthesis; D000818:Animals; D002450:Cell Communication; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006133:Growth Substances / Q000096:biosynthesis; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008970:Molecular Weight; D010960:Plasminogen Activators / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D012670:Seminiferous Epithelium / Q000378:metabolism*; D012708:Sertoli Cells / Q000378:metabolism*; D013735:Testicular Hormones / Q000302:isolation & purification / Q000502:physiology*; D013737:Testis / Q000378:metabolism* / Q000502:physiology; D013739:Testosterone / Q000494:pharmacology; D014168:Transferrin / Q000096:biosynthesis; D014801:Vitamin A / Q000494:pharmacology
D000727:Androgen-Binding Protein; D006133:Growth Substances; D007328:Insulin; D013735:Testicular Hormones; D014168:Transferrin; D014801:Vitamin A; D013739:Testosterone; D005640:Follicle Stimulating Hormone; D004247:DNA; D010960:Plasminogen Activators