| Co-Investigator(Kenkyū-buntansha) |
YASUDA Masanori School of Medicine, Tokai University, Assistant Researcher, 医学部, 助手 (50242508)
SHIBUYA Makoto School of Medicine, Tokai University, Assistant Professor, 医学部, 講師 (50201546)
TAKEKOSHI Susumu School of Medicine, Tokai University, Assistant Researcher, 医学部, 助手 (70216878)
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| Research Abstract |
Continuing from 1998, we have studied various transcription factors and receptors in pituitary hormone production by immunohistochemisty and RT-PCR. During 1999, we have particularly emphasized the analysis of pituitary homeobox 1 (Ptx1) in the human and rat pituitary glands as well as various human pituitary adenomas. Both in the rat and human pituitary glands, Ptx1 was localized in all kinds of pituitary hormone producing cells including GH, PRL, TSH, ACTH and LH/FSH. It was of our particular interests that Ptx1 was identified in folliculo-stellate (FS) cells. FS cells have been claimed to produce various cytokines in stead of pituitary hormones. In the pituitary adenomas, Ptx1 was present in various types including GH secreting, PRL secreting, TSH secreting, ACTH secreting, LH/FSH secreting and non-functioning ones. These data suggested that Ptx1 is a universal transcription factor and synergistic action with the other transcription factors is essential to promote the individual hormone production. The presence of Ptx1 may suggest the common ancestor of FS cells with the pituitary hormone producing cells.
To further clarify the mechanism of ACTH production in human pituitary adenomas, we investigated the role of transcription factor NeuroD1. Among various adenomas, NeuroD1 was localized in the groups of ACTH secreting and non-functioning adenomas. In ACTH secreting adenomas, it was suggested that the synergistic action between Ptx1 and NeuroD1 may be the basic molecular mechanism for ACTH production. Its role of in non-functioning adenomas remains to be further investigated.
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