Rat Sertoli cell extracellular matrix regulates glycosaminoglycan synthesis by peritubular myoid cells in vitro

We have previously reported metabolic cooperation between Sertoli and peritubular myoid cells in terms of synthesis of one of the main testicular extracellular matrix (ECM) constituents, glycosaminoglycans (GAG). This study concerns Sertoli cell ECM-peritubular myoid cell interactions in terms of GAG synthesis. We have examined the responses of hormones and other regulatory agents such as a combination of follicle-stimulating hormone (FSH), insulin, retinol, and testosterone (FIRT) on peritubular myoid cells, and tested if Sertoli cell ECM or serum factor substitute for the stimulation by FIRT. Testicular peritubular myoid cells cultured on Sertoli cell ECM showed significant increases in the levels of cell- and ECM-associated GAG over that when cultured on uncoated plastic. This indicates a specific cell-substratum interaction between Sertoli cell ECM and peritubular myoid cells in the testis in terms of GAG synthesis. Moreover, in terms of cell-associated GAG synthesis, peritubular myoid cell cultured on Sertoli cell ECM or on plastic in the presence of serum substituted for the stimulatory response of FIRT on peritubular myoid cells cultured on uncoated plastic. The data are discussed in relation to the possible role of cell-substratum interaction in maintaining peritubular myoid cell functions.