Prolactin receptors are expressed and hormonally regulated in rat Sertoli cells.

Abstract In this study, the protein and mRNA expression of the short and long forms of Prolactin (PRL) receptors (PRL-R) were examined by means of Northern and Western blotting analyses in rat testicular Sertoli cells. Transcripts for the short and long forms of PRL-R were detected with specific probes, five major mRNA species of about 1.9, 2.6, 3.0, 3.7 and 5 kb for the short form and two of about 10 and 1.3 kb for the long form. Under reducing conditions, the use of a specific antibody for the short form revealed a major molecular species of ≈45 kDa. Two groups of molecular species were detected for the long form, several bands with high molecular masses (110–300 kDa) and others about 45–60 kDa. Finally, the expression of the long form of PRL-R was shown to be hormonally regulated as it was inhibited by follicle stimulating hormone (FSH) (ED 50 =5 ng/ml). Together, the localisation of PRL receptors to Sertoli cells as well as the regulatory action of FSH on these receptors suggest that PRL and or (a) PRL-like activity(ies) might be considered as (a) potential regulator(s) of spermatogenesis.