Expression of Pit-1 mRNA and activin/inhibin subunits in clinically nonfunctioning pituitary adenomas. In situ hybridization and immunohistochemical analysis.
The pituitary-specific transcriptional factor Pit-1 is known to play a role in the development and differentiation of pituitary cells. Recent investigations have suggested a role for this transcriptional factor in pituitary adenomas, especially growth hormone (GH)- and prolactin (PRL)-secreting pituitary adenomas. In this study we analyzed the expression of Pit-1 mRNA and its protein in 24 clinically nonfunctioning pituitary adenomas in comparison with normal pituitary glands using in situ hybridization (ISH) and immunohistochemistry (IHC). The interaction between inhibin/activin, a member of the transforming growth factor-beta family, and Pit-1 was also studied. Immunohistochemically, Pit-1 protein was detected in 9 of 24 adenomas (37.5 %), and 8 of these 9 were also positive for the alpha subunit of glycoprotein (alphaSU). The expression of Pit-1 mRNA was detected in 14 of 24 (58.3%) clinically nonfunctioning adenomas, and it was found in all cases which expressed the Pit-1 protein. By the combined ISH and IHC method, Pit-1 mRNA was frequently observed in alphaSU-immunopositive cells in adenomas. The inhibin/activin alpha subunit was detected in all 24 adenomas and the betaA subunit was detected in 13 of 24 adenomas. The inhibin/activin betaA subunit was detected frequently with Pit-1 mRNA. From our observations, the inhibin/activin betaA subunit in nonfunctioning adenomas may have related the expression of Pit- mRNA in these adenomas.
Department of Neurosurgery, Nippon Medical School, Tokyo, Japan.
N
N
Sanno
A
A
Teramoto
M
M
Sugiyama
A
A
Matsuno
I
I
Takumi
S
S
Tahara
R Y
RY
Osamura
D028341:Activins; D000236:Adenoma / Q000737:chemistry* / Q000235:genetics; D000328:Adult; D000368:Aged; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000032:analysis; D037201:Follicle Stimulating Hormone, beta Subunit; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007265:Inhibins / Q000032:analysis*; D007986:Luteinizing Hormone / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000737:chemistry* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D050817:Transcription Factor Pit-1; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D037201:Follicle Stimulating Hormone, beta Subunit; C494187:POU1F1 protein, human; D012333:RNA, Messenger; D050817:Transcription Factor Pit-1; D014157:Transcription Factors; D028341:Activins; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone