Signal transducers and activators of transcription 1 and 3 in prostate: effect of sexual activity.

The signal transducers and activators of transcription (Stat) are effector molecules downstream of cytokine receptors. Ligand occupancy of these receptors results in the tyrosine phosphorylation, dimerization and nuclear translocation of the Stat family of transcription factors and by these means regulate gene expression. Prolactin receptors as members of the cytokine-hematopoietin receptor superfamily, are linked to Stat activation. Sexual stimulation leads to an increase in prolactin secretion that might be involved in long-term changes in the protein repertoire associated to prostate hyperplasia. In order to gain insight into this phenomenon, we analyzed the tyrosine phosphorylation and DNA binding activity of two members of the Stat family in the prostate of sexual experienced rats after different number of ejaculations. A significant increase in Stat-1 and Stat-3 tyrosine phosphorylation was found after three ejaculations. Concomitantly an increase in Stat-1 and Stat-3 DNA-binding activity is detected after two and three ejaculation series. These results, favor the notion that ejaculation-induced prolactin secretion activates its prostate receptors resulting in Stat-1 and Stat-3 nuclear translocation, event likely to be associated to the so-called benign prostate hyperplasia.