Prolactin binding in normal human minor salivary gland tissue: an immunohistochemical study

The breast and salivary gland exhibit some similarities in the biochemical and cellular spheres. There are also some tumors that are common to both organs. The protein hormone prolactin seems to play a role in the health and disease of the mammary gland, and an investigation was launched to see if this hormone exhibited any binding activity in normal human minor salivary gland. With the use of immunohistochemical methods, dose-dependent staining for prolactin binding was demonstrated in the striated and collecting ducts in four of six specimens of normal human minor salivary gland (two males and two females). The hormone concentrations used ranged from 6.25 ng/ml to 500 ng/ml of highly purified rat prolactin. A review of known functions of prolactin in man and other animals is presented, and it was concluded that normal human minor salivary gland tissue possesses binding sites for prolactin, which suggests that prolactin may play a role in the metabolic functioning of the salivary duct cells.