The use of specific cDNA probes to assay Sertoli cell functions

The use of cDNA probes to measure the functional state of Sertoli cells in culture or in vivo offers a number of advantages, including sensitivity and cellular specificity. Experiments done with cultured Sertoli cells suggest that the transferrin mRNA levels are regulated by FSH, insulin, vitamin A, and testosterone. Questions relating to the specificity of the action of the hormones and vitamin A on the transferrin mRNA or on other mRNA will require the use of additional hybridization probes. It is clear that most agents which stimulate spermatogenesis also stimulate transferrin mRNA accumulation in cultured Sertoli cells. Testosterone, however, has only a small stimulatory effect on the cultured Sertoli cells. In the in vivo measurements we have completed thus far, the level of transferrin mRNA in the testis seems to correlate well with the spermatogenic condition of the testis. In immature rats, hypophysectomized rats, and vitamin A deficient rats, spermatogenesis is abbreviated and the levels of transferrin mRNA in the Sertoli cells are correspondingly low. If this correlation holds up under additional scrutiny, assays of the transferrin mRNA levels may be effective screens for the toxic or stimulatory activities of a variety of pharmaceuticals which could affect spermatogenesis.