Expression of hypothalamic hormone receptors in pituitary adenomas

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The hormonal secretion of the pituitary gland is controlled by the inhibitory factor or the stimulating factor from the hypothalamus. To date, expression of several hypothalamic hormones and receptors in the pituitary gland have been reported, and their role for tumorigenesis, cell differentiation and cell growth are suggestied. In this study, we investigated the expression of various hypothalamus hormone receptors and transcription factors in human normal pituitaries and different types of human pituitary adenomas using the RT-PCR and immunohistochemical techniques, and aimed to clarify their contribution to tumorigenesis, cell differentiation and cell growth. Concerning about transcription factors, we examined PTX-1,Neuro D1,Pit-1 and Estrogen receptor(ER). PTX-1 and Neuro D1 were expressed in all types of pituitary adenomas. Pit-1 was especially expressed in GH secreting, PRL secreting and TSH secreting adenomas, and also expressed in some non-functioning adenomas, that indicate Pit-1 may be influenced by a-subunit. ER was expressed in PRL secreting and gonadal hormone secreting adenomas, that indicate ER has interaction with Pit-1. Concerning about hypothalamic hormones and their receptors, we studied the expression of GHS-R and TRH-R. Their strong expressions in all GH secreting adenomas were showed by RT-PCR study and immunohistochemical study including in situ hybridization method. We also investigated the expression of Ghrelin, strong endogenious ligands for GHS-R, in pituitary adenomas, there exist no correlation between them. Our result suggest that transcription factors have interaction with hypothalamic hormones and its receptors, and they have some contributions to tumorigenesis, cell differentiation and cell growth of pituitary adenomas.