Prolactin receptor gene diversity: structure and regulation.

The diverse functionality of prolactin and the wide expression of the prolactin receptor suggest a complex system regulated by this polypeptide hormone. Different hormone and receptor forms, as well as differential signal transduction pathways, contribute to the functional diversity of prolactin's actions. The heterogeneity of rat prolactin receptor gene transcripts in their 5'-untranslated region has led to the recognition of multiple and tissue-specific utilization of prolactin receptor gene promoters in gonadal and non-gonadal tissues. These findings have provided insights into the molecular bases for the diversity of prolactin's actions. It is now clear that cellular responsiveness to prolactin can be regulated through differential promoter control of the expression of the surface receptors for prolactin in different target tissues.