
<ArticleTitle>Expression of <prot>neuro D1</prot> in human normal pituitaries and pituitary adenomas.</ArticleTitle>
<AbstractText><prot>Neuro D1</prot> is a basic helix-loop-helix transcription factor expressed in the endocrine cells of pancreas and in a subset of neurons as they undergo terminal differentiation. In the adult pituitary gland, <prot>Neuro D1</prot> is expressed in corticotroph cells and contributes to the corticotroph-specific pro-opiomelanocortin (POMC) transcription by interacting with <prot>Pituitary homeobox 1</prot> (<prot>Ptx 1</prot>) transcription factor. In the present study, we investigated the expression of <prot>Neuro D1</prot> in human normal pituitaries and different types of human pituitary adenomas using the RT-PCR and immunohistochemical techniques. Using RT-PCR, <prot>Neuro D1</prot> mRNA was found to be expressed in ACTH-secreting adenomas (n = 3) and 6 of 8 non-functioning adenomas. On the other hand, GH-secreting adenomas (n = 5) and PRL-secreting adenomas (n = 3) were completely negative for <prot>Neuro D1</prot> mRNA. Immunohistochemically, <prot>Neuro D1</prot> was expressed in all ACTH-secreting adenomas (n = 10), and in 14 of 20 nonfunctioning adenomas. In contrast, 3 of 10 PRL-secreting adenomas and 2 of 10 GH-secreting adenomas showed positive <prot>Neuro D1</prot> staining in the nuclei. The above results suggest that <prot>Neuro D1</prot> contribute to the functional expression and the differentiation of ACTH-secreting adenomas. It also appears from our study that <prot>Neuro D1</prot> might play a role in the differentiation of non-functioning adenomas, the mechanism of which remains to be further investigated. This is the first study on <prot>Neuro D1</prot> in case of human pituitary adenomas.</AbstractText>
