Absence of thyroid transcription factor-1 expression in human parathyroid and pituitary glands

Thyroid transcription factor-1 (TTF-1). a tissue-specific nuclear transcrip tion factor involved in the embryogenesis and differentiation of human thyr oid, lung and brain, has been recently identified in other rat tissues, inc luding parafollicular C cells and parathyroid chief cells. Based on this di stribution, a possible role for this factor in calcium homeostasis has been suggested. This study investigated the presence of TTF-1 transcripts and p rotein in human tissues expressing the calcium sensing receptor (CaSR). Usi ng a RT-PCR technique. complemented by Southern blot analysis, TTF-1 expres sion was detected in human C cells (two medullary thyroid carcinomas), but not in normal and adenomatous (four adenomas and three hyperplasia) parathy roid. and normal and adenomatous (six adenomas) pituitary tissues. CaSR was expressed in all samples. The absence of expression was confirmed by Weste rn blot. In contrast to previous studies in the rat, this study demonstrate s the absence of TTF-1 transcripts in the human adult parathyroid and pitui tary glands, although a role for this factor during the ontogeny of these o rgans cannot be excluded. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.