Objective: mPOU is a POU protein classified as class VI. It is present in the pituitary gland as well as the brain, heart muscle, skeletal muscle, lung, and lymphocytes. In our previous investigation, mPOU bound to the Pit-1-binding DNA elements of the rat PRL gene, and promoted transcription of the GH and PRL genes. In this study, we immunohistologically investigated the expression of mPOU in pituitary adenomas.
Methods: 17 patients with pituitary adenoma underwent tumor excision by transsphenoidal approach at our hospital (PRL: 5, GH: 4, FSH: 1, non-functioning: 7). The expression in the tissue sections was investigated using immunostaining (ABC method).
Results: In all GH-producing and PRL-producing adenomas, mPOU protein was specifically expressed, particularly in the nuclei.
Discussion: Pit-1 has been considered to be a factor determining the expression of GH and PRL genes, but mPOU may also be involved in the expression.